diff --git a/java/com/google/gerrit/plugins/codeowners/acceptance/AbstractCodeOwnersIT.java b/java/com/google/gerrit/plugins/codeowners/acceptance/AbstractCodeOwnersIT.java
index 8ea5a5b..f7a2943 100644
--- a/java/com/google/gerrit/plugins/codeowners/acceptance/AbstractCodeOwnersIT.java
+++ b/java/com/google/gerrit/plugins/codeowners/acceptance/AbstractCodeOwnersIT.java
@@ -25,7 +25,6 @@
 import com.google.gerrit.plugins.codeowners.api.impl.ProjectCodeOwnersFactory;
 import com.google.gerrit.plugins.codeowners.backend.CodeOwnerBackendId;
 import com.google.gerrit.plugins.codeowners.backend.config.BackendConfig;
-import com.google.gerrit.plugins.codeowners.backend.config.GeneralConfig;
 import com.google.gerrit.plugins.codeowners.backend.proto.ProtoBackend;
 import com.google.gerrit.testing.ConfigSuite;
 import java.util.Arrays;
@@ -45,26 +44,6 @@
  */
 public class AbstractCodeOwnersIT extends AbstractCodeOwnersTest {
   /**
-   * Returns a {@code gerrit.config} without code owner backend configuration to test the default
-   * setup.
-   */
-  @ConfigSuite.Default
-  public static Config defaultConfig() {
-    Config cfg = new Config();
-
-    // Disable asynchronous posting of change messages during tests to avoid parallel updates to
-    // NoteDb and hence risking LOCK_FAILURES (especially needed since the test API does not retry
-    // on LOCK_FAILURES).
-    cfg.setBoolean(
-        "plugin",
-        "code-owners",
-        GeneralConfig.KEY_ENABLE_ASYNC_MESSAGE_ON_ADD_REVIEWER,
-        /* value= */ false);
-
-    return cfg;
-  }
-
-  /**
    * Returns a {@code gerrit.config} for every code owner backend so that all code owner backends
    * are tested.
    */
diff --git a/java/com/google/gerrit/plugins/codeowners/acceptance/AbstractCodeOwnersTest.java b/java/com/google/gerrit/plugins/codeowners/acceptance/AbstractCodeOwnersTest.java
index fda3e52..1283932 100644
--- a/java/com/google/gerrit/plugins/codeowners/acceptance/AbstractCodeOwnersTest.java
+++ b/java/com/google/gerrit/plugins/codeowners/acceptance/AbstractCodeOwnersTest.java
@@ -43,10 +43,12 @@
 import com.google.gerrit.plugins.codeowners.backend.CodeOwnerConfigReference;
 import com.google.gerrit.plugins.codeowners.backend.config.BackendConfig;
 import com.google.gerrit.plugins.codeowners.backend.config.CodeOwnersPluginConfiguration;
+import com.google.gerrit.plugins.codeowners.backend.config.GeneralConfig;
 import com.google.gerrit.plugins.codeowners.backend.config.StatusConfig;
 import com.google.gerrit.plugins.codeowners.backend.findowners.FindOwnersBackend;
 import com.google.gerrit.plugins.codeowners.backend.proto.ProtoBackend;
 import com.google.gerrit.plugins.codeowners.util.JgitPath;
+import com.google.gerrit.testing.ConfigSuite;
 import com.google.inject.Inject;
 import java.nio.file.Path;
 import java.util.Map;
@@ -72,6 +74,31 @@
     name = "code-owners",
     sysModule = "com.google.gerrit.plugins.codeowners.acceptance.TestModule")
 public class AbstractCodeOwnersTest extends LightweightPluginDaemonTest {
+  /**
+   * Returns a {@code gerrit.config} without code owner backend configuration to test the default
+   * setup.
+   */
+  @ConfigSuite.Default
+  public static Config defaultConfig() {
+    Config cfg = new Config();
+
+    // Disable asynchronous posting of change messages during tests to avoid parallel updates to
+    // NoteDb and hence risking LOCK_FAILURES (especially needed since the test API does not retry
+    // on LOCK_FAILURES).
+    cfg.setBoolean(
+        "plugin",
+        "code-owners",
+        GeneralConfig.KEY_ENABLE_ASYNC_MESSAGE_ON_ADD_REVIEWER,
+        /* value= */ false);
+    cfg.setBoolean(
+        "plugin",
+        "code-owners",
+        GeneralConfig.KEY_ENABLE_ASYNC_MESSAGE_ON_CODE_OWNER_APPROVAL,
+        /* value= */ false);
+
+    return cfg;
+  }
+
   @Inject private ProjectOperations projectOperations;
 
   private CodeOwnerConfigOperations codeOwnerConfigOperations;
diff --git a/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java b/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java
index 67532c1..e7c03b1 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java
@@ -15,6 +15,8 @@
 package com.google.gerrit.plugins.codeowners.backend;
 
 import static com.google.common.base.Preconditions.checkState;
+import static com.google.gerrit.server.update.context.RefUpdateContext.RefUpdateType.CHANGE_MODIFICATION;
+import static com.google.gerrit.server.update.context.RefUpdateContext.RefUpdateType.PLUGIN;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.flogger.FluentLogger;
@@ -25,11 +27,20 @@
 import com.google.gerrit.plugins.codeowners.backend.config.RequiredApproval;
 import com.google.gerrit.plugins.codeowners.metrics.CodeOwnerMetrics;
 import com.google.gerrit.plugins.codeowners.util.JgitPath;
+import com.google.gerrit.server.ChangeMessagesUtil;
 import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.git.WorkQueue;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.restapi.change.OnPostReview;
+import com.google.gerrit.server.update.BatchUpdate;
+import com.google.gerrit.server.update.BatchUpdateOp;
+import com.google.gerrit.server.update.ChangeContext;
+import com.google.gerrit.server.update.RetryHelper;
+import com.google.gerrit.server.update.context.RefUpdateContext;
 import com.google.gerrit.server.util.AccountTemplateUtil;
 import com.google.gerrit.server.util.LabelVote;
+import com.google.gerrit.server.util.ManualRequestContext;
+import com.google.gerrit.server.util.OneOffRequestContext;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
 import java.nio.file.Path;
@@ -55,18 +66,33 @@
 class OnCodeOwnerApproval implements OnPostReview {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
+  private static final String TAG_ADD_CODE_OWNER_APPROVAL =
+      ChangeMessagesUtil.AUTOGENERATED_BY_GERRIT_TAG_PREFIX + "code-owners:addCodeOwnerApproval";
+
+  private final WorkQueue workQueue;
+  private final OneOffRequestContext oneOffRequestContext;
   private final CodeOwnersPluginConfiguration codeOwnersPluginConfiguration;
   private final CodeOwnerApprovalCheck codeOwnerApprovalCheck;
   private final CodeOwnerMetrics codeOwnerMetrics;
+  private final ChangeMessagesUtil changeMessageUtil;
+  private final RetryHelper retryHelper;
 
   @Inject
   OnCodeOwnerApproval(
+      WorkQueue workQueue,
+      OneOffRequestContext oneOffRequestContext,
       CodeOwnersPluginConfiguration codeOwnersPluginConfiguration,
       CodeOwnerApprovalCheck codeOwnerApprovalCheck,
-      CodeOwnerMetrics codeOwnerMetrics) {
+      CodeOwnerMetrics codeOwnerMetrics,
+      ChangeMessagesUtil changeMessageUtil,
+      RetryHelper retryHelper) {
+    this.workQueue = workQueue;
+    this.oneOffRequestContext = oneOffRequestContext;
     this.codeOwnersPluginConfiguration = codeOwnersPluginConfiguration;
     this.codeOwnerApprovalCheck = codeOwnerApprovalCheck;
     this.codeOwnerMetrics = codeOwnerMetrics;
+    this.changeMessageUtil = changeMessageUtil;
+    this.retryHelper = retryHelper;
   }
 
   @Override
@@ -99,6 +125,33 @@
       return Optional.empty();
     }
 
+    if (codeOwnersConfig.enableAsyncMessageOnCodeOwnerApproval()) {
+      // post change message asynchronously to avoid adding latency to PostReview
+      logger.atFine().log("schedule asynchronous posting of the change message");
+      @SuppressWarnings("unused")
+      WorkQueue.Task<?> possiblyIgnoredError =
+          (WorkQueue.Task<?>)
+              workQueue
+                  .getDefaultQueue()
+                  .submit(
+                      () -> {
+                        try (ManualRequestContext ignored =
+                            oneOffRequestContext.openAs(user.getAccountId())) {
+                          postChangeMessage(
+                              when,
+                              user,
+                              changeNotes,
+                              patchSet,
+                              oldApprovals,
+                              approvals,
+                              requiredApproval,
+                              maxPathsInChangeMessage);
+                        }
+                      });
+      return Optional.empty();
+    }
+
+    logger.atFine().log("post change message synchronously");
     try (Timer0.Context ctx = codeOwnerMetrics.extendChangeMessageOnPostReview.start()) {
       return buildMessageForCodeOwnerApproval(
           user,
@@ -128,6 +181,58 @@
     }
   }
 
+  private void postChangeMessage(
+      Instant when,
+      IdentifiedUser user,
+      ChangeNotes changeNotes,
+      PatchSet patchSet,
+      Map<String, Short> oldApprovals,
+      Map<String, Short> approvals,
+      RequiredApproval requiredApproval,
+      int maxPathsInChangeMessages) {
+    try (Timer0.Context ctx = codeOwnerMetrics.addChangeMessageOnCodeOwnerApproval.start()) {
+      retryHelper
+          .changeUpdate(
+              "addCodeOwnersMessageOnCodeOwnerApproval",
+              updateFactory -> {
+                try (BatchUpdate batchUpdate =
+                        updateFactory.create(changeNotes.getProjectName(), user, when);
+                    RefUpdateContext pluginCtx = RefUpdateContext.open(PLUGIN);
+                    RefUpdateContext changeCtx = RefUpdateContext.open(CHANGE_MODIFICATION)) {
+                  batchUpdate.addOp(
+                      changeNotes.getChangeId(),
+                      new Op(
+                          user,
+                          changeNotes,
+                          patchSet,
+                          oldApprovals,
+                          approvals,
+                          requiredApproval,
+                          maxPathsInChangeMessages));
+                  batchUpdate.execute();
+                }
+                return null;
+              })
+          .call();
+    } catch (Exception e) {
+      Optional<? extends Exception> configurationError =
+          CodeOwnersExceptionHook.getCauseOfConfigurationError(e);
+      if (configurationError.isPresent()) {
+        logger.atWarning().log(
+            "Failed to post code-owners change message for code owner approval on change %s in"
+                + " project %s: %s",
+            changeNotes.getChangeId(),
+            changeNotes.getProjectName(),
+            configurationError.get().getMessage());
+      } else {
+        logger.atSevere().withCause(e).log(
+            "Failed to post code-owners change message for code owner approval on change %s in"
+                + " project %s.",
+            changeNotes.getChangeId(), changeNotes.getProjectName());
+      }
+    }
+  }
+
   private Optional<String> buildMessageForCodeOwnerApproval(
       IdentifiedUser user,
       ChangeNotes changeNotes,
@@ -292,4 +397,48 @@
         approvals);
     return LabelVote.create(labelName, approvals.get(labelName));
   }
+
+  private class Op implements BatchUpdateOp {
+    private final IdentifiedUser user;
+    private final ChangeNotes changeNotes;
+    private final PatchSet patchSet;
+    private final Map<String, Short> oldApprovals;
+    private final Map<String, Short> approvals;
+    private final RequiredApproval requiredApproval;
+    private final int limit;
+
+    Op(
+        IdentifiedUser user,
+        ChangeNotes changeNotes,
+        PatchSet patchSet,
+        Map<String, Short> oldApprovals,
+        Map<String, Short> approvals,
+        RequiredApproval requiredApproval,
+        int limit) {
+      this.user = user;
+      this.changeNotes = changeNotes;
+      this.patchSet = patchSet;
+      this.oldApprovals = oldApprovals;
+      this.approvals = approvals;
+      this.requiredApproval = requiredApproval;
+      this.limit = limit;
+    }
+
+    @Override
+    public boolean updateChange(ChangeContext ctx) throws Exception {
+      Optional<String> message =
+          buildMessageForCodeOwnerApproval(
+              user, changeNotes, patchSet, oldApprovals, approvals, requiredApproval, limit);
+
+      if (message.isEmpty()) {
+        return false;
+      }
+
+      changeMessageUtil.setChangeMessage(
+          ctx,
+          String.format("Patch Set %s: %s", patchSet.id().get(), message.get()),
+          TAG_ADD_CODE_OWNER_APPROVAL);
+      return true;
+    }
+  }
 }
diff --git a/java/com/google/gerrit/plugins/codeowners/backend/config/CodeOwnersPluginProjectConfigSnapshot.java b/java/com/google/gerrit/plugins/codeowners/backend/config/CodeOwnersPluginProjectConfigSnapshot.java
index f02e54d..786d3e4 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/config/CodeOwnersPluginProjectConfigSnapshot.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/config/CodeOwnersPluginProjectConfigSnapshot.java
@@ -84,6 +84,7 @@
   @Nullable private FallbackCodeOwners fallbackCodeOwners;
   @Nullable private Integer maxPathsInChangeMessages;
   @Nullable private Boolean enableAsyncMessageOnAddReviewer;
+  @Nullable private Boolean enableAsyncMessageOnCodeOwnerApproval;
   @Nullable private ImmutableSet<CodeOwnerReference> globalCodeOwners;
   @Nullable private ImmutableSet<Account.Id> exemptedAccounts;
   @Nullable private Optional<String> overrideInfoUrl;
@@ -333,6 +334,18 @@
     return enableAsyncMessageOnAddReviewer;
   }
 
+  /**
+   * Gets whether applying a code owner approval should post a change message asynchronously instead
+   * of synchronously extending the change message that is posted by Gerrit core.
+   */
+  public boolean enableAsyncMessageOnCodeOwnerApproval() {
+    if (enableAsyncMessageOnCodeOwnerApproval == null) {
+      enableAsyncMessageOnCodeOwnerApproval =
+          generalConfig.enableAsyncMessageOnCodeOwnerApproval(projectName, pluginConfig);
+    }
+    return enableAsyncMessageOnCodeOwnerApproval;
+  }
+
   /** Gets the global code owners. */
   public ImmutableSet<CodeOwnerReference> getGlobalCodeOwners() {
     if (globalCodeOwners == null) {
diff --git a/java/com/google/gerrit/plugins/codeowners/backend/config/GeneralConfig.java b/java/com/google/gerrit/plugins/codeowners/backend/config/GeneralConfig.java
index 810486f..ada9105 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/config/GeneralConfig.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/config/GeneralConfig.java
@@ -65,6 +65,8 @@
   public static final String KEY_FILE_EXTENSION = "fileExtension";
   public static final String KEY_ENABLE_ASYNC_MESSAGE_ON_ADD_REVIEWER =
       "enableAsyncMessageOnAddReviewer";
+  public static final String KEY_ENABLE_ASYNC_MESSAGE_ON_CODE_OWNER_APPROVAL =
+      "enableAsyncMessageOnCodeOwnerApproval";
   public static final String KEY_ENABLE_CODE_OWNER_CONFIG_FILES_WITH_FILE_EXTENSIONS =
       "enableCodeOwnerConfigFilesWithFileExtensions";
   public static final String KEY_READ_ONLY = "readOnly";
@@ -476,6 +478,25 @@
   }
 
   /**
+   * Gets whether applying a code owner approval should post a change message asynchronously instead
+   * of synchronously extending the change message that is posted by Gerrit core.
+   *
+   * @param project the project for which the enable async message on code owner approval
+   *     configuration should be read
+   * @param pluginConfig the plugin config from which the enable async message on code owner
+   *     approval configuration should be read
+   * @return whether applying a code owner approval should post a change message asynchronously
+   *     instead of synchronously extending the change message that is posted by Gerrit core
+   */
+  boolean enableAsyncMessageOnCodeOwnerApproval(Project.NameKey project, Config pluginConfig) {
+    return getBooleanConfig(
+        project,
+        pluginConfig,
+        KEY_ENABLE_ASYNC_MESSAGE_ON_CODE_OWNER_APPROVAL,
+        /* defaultValue= */ true);
+  }
+
+  /**
    * Gets the enable validation on branch creation configuration from the given plugin config for
    * the specified project with fallback to {@code gerrit.config} and default to {@code true}.
    *
diff --git a/java/com/google/gerrit/plugins/codeowners/metrics/CodeOwnerMetrics.java b/java/com/google/gerrit/plugins/codeowners/metrics/CodeOwnerMetrics.java
index fa90564..4a6c37d 100644
--- a/java/com/google/gerrit/plugins/codeowners/metrics/CodeOwnerMetrics.java
+++ b/java/com/google/gerrit/plugins/codeowners/metrics/CodeOwnerMetrics.java
@@ -33,6 +33,7 @@
 public class CodeOwnerMetrics {
   // latency metrics
   public final Timer1<String> addChangeMessageOnAddReviewer;
+  public final Timer0 addChangeMessageOnCodeOwnerApproval;
   public final Timer0 computeFileStatus;
   public final Timer1<Boolean> computeFileStatuses;
   public final Timer0 computeOwnedPaths;
@@ -85,6 +86,11 @@
                 .description(
                     "Whether the change message was posted synchronously or asynchronously.")
                 .build());
+    this.addChangeMessageOnCodeOwnerApproval =
+        createTimer(
+            "add_change_message_on_code_owner_approval",
+            "Latency for asynchronously adding a change message with the owned path when a code"
+                + " owner approval is applied");
     this.computeFileStatus =
         createTimer("compute_file_status", "Latency for computing the file status of one file");
     this.computeFileStatuses =
@@ -105,8 +111,8 @@
     this.extendChangeMessageOnPostReview =
         createTimer(
             "extend_change_message_on_post_review",
-            "Latency for extending the change message with the owned path when a code owner"
-                + " approval is applied");
+            "Latency for synchronously extending the change message with the owned path when a"
+                + " code owner approval is applied");
     this.getChangedFiles =
         createTimer("get_changed_files", "Latency for getting changed files from diff cache");
     this.prepareFileStatusComputation =
diff --git a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/CodeOwnersPluginConfigValidatorIT.java b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/CodeOwnersPluginConfigValidatorIT.java
index b2a6630..b0caf0a 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/CodeOwnersPluginConfigValidatorIT.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/CodeOwnersPluginConfigValidatorIT.java
@@ -631,6 +631,27 @@
   }
 
   @Test
+  public void configureEnableAsyncMessageOnCodeOwnerApproval() throws Exception {
+    fetchRefsMetaConfig();
+
+    Config cfg = new Config();
+    cfg.setBoolean(
+        CodeOwnersPluginConfiguration.SECTION_CODE_OWNERS,
+        /* subsection= */ null,
+        GeneralConfig.KEY_ENABLE_ASYNC_MESSAGE_ON_CODE_OWNER_APPROVAL,
+        false);
+    setCodeOwnersConfig(cfg);
+
+    PushResult r = pushRefsMetaConfig();
+    assertThat(r.getRemoteUpdate(RefNames.REFS_CONFIG).getStatus()).isEqualTo(Status.OK);
+    assertThat(
+            codeOwnersPluginConfiguration
+                .getProjectConfig(project)
+                .enableAsyncMessageOnCodeOwnerApproval())
+        .isFalse();
+  }
+
+  @Test
   public void cannotSetInvalidMaxPathsInChangeMessages() throws Exception {
     fetchRefsMetaConfig();
 
diff --git a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerApprovalIT.java b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerApprovalIT.java
index d3fe19a..7d7a99a 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerApprovalIT.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerApprovalIT.java
@@ -16,7 +16,10 @@
 
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS;
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
 
+import com.github.rholder.retry.RetryerBuilder;
+import com.github.rholder.retry.StopStrategies;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;
@@ -34,12 +37,22 @@
 import com.google.gerrit.server.util.AccountTemplateUtil;
 import com.google.gerrit.testing.FakeEmailSender.Message;
 import com.google.inject.Inject;
+import java.time.Duration;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
+import java.util.concurrent.Callable;
 import org.junit.Test;
 
-/** Acceptance test for {@code com.google.gerrit.plugins.codeowners.backend.OnCodeOwnerApproval}. */
+/**
+ * Acceptance test for {@code com.google.gerrit.plugins.codeowners.backend.OnCodeOwnerApproval}.
+ *
+ * <p>For tests the change message that is posted when a code owner approval is applied, is added
+ * synchronously by default (see {@link AbstractCodeOwnersIT #defaultConfig()}). Tests that want to
+ * verify the asynchronous posting of this change message need to set {@code
+ * plugin.code-owners.enableAsyncMessageOnCodeOwnerApproval=true} in {@code gerrit.config}
+ * explicitly (by using the {@link GerritConfig} annotation).
+ */
 public class OnCodeOwnerApprovalIT extends AbstractCodeOwnersIT {
   @Inject private RequestScopeOperations requestScopeOperations;
   @Inject private ProjectOperations projectOperations;
@@ -1143,4 +1156,49 @@
                     + "* %s\n",
                 user.fullName(), user.email(), path));
   }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.enableAsyncMessageOnCodeOwnerApproval", value = "true")
+  public void changeMessageListsNewlyApprovedPaths_async() throws Exception {
+    codeOwnerConfigOperations
+        .newCodeOwnerConfig()
+        .project(project)
+        .branch("master")
+        .folderPath("/foo/")
+        .addCodeOwnerEmail(admin.email())
+        .create();
+
+    String path = "foo/bar.baz";
+    String changeId = createChange("Test Change", path, "file content").getChangeId();
+
+    recommend(changeId);
+
+    assertAsyncChangeMessage(
+        changeId,
+        String.format(
+            "Patch Set 1: "
+                + "By voting Code-Review+1 the following files are now code-owner approved by"
+                + " %s:\n"
+                + "* %s\n",
+            AccountTemplateUtil.getAccountTemplate(admin.id()), path));
+  }
+
+  private void assertAsyncChangeMessage(String changeId, String expectedChangeMessage)
+      throws Exception {
+    assertAsync(
+        () -> {
+          Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
+          assertThat(Iterables.getLast(messages).message).isEqualTo(expectedChangeMessage);
+          return null;
+        });
+  }
+
+  private <T> T assertAsync(Callable<T> assertion) throws Exception {
+    return RetryerBuilder.<T>newBuilder()
+        .retryIfException(t -> true)
+        .withStopStrategy(
+            StopStrategies.stopAfterDelay(Duration.ofSeconds(1).toMillis(), MILLISECONDS))
+        .build()
+        .call(() -> assertion.call());
+  }
 }
diff --git a/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheckWithAllUsersAsFallbackCodeOwnersTest.java b/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheckWithAllUsersAsFallbackCodeOwnersTest.java
index 5c31eed..b6c3a43 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheckWithAllUsersAsFallbackCodeOwnersTest.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheckWithAllUsersAsFallbackCodeOwnersTest.java
@@ -52,7 +52,7 @@
   /** Returns a {@code gerrit.config} that configures all users as fallback code owners. */
   @ConfigSuite.Default
   public static Config defaultConfig() {
-    Config cfg = new Config();
+    Config cfg = AbstractCodeOwnersTest.defaultConfig();
     cfg.setEnum(
         "plugin",
         "code-owners",
diff --git a/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheckWithSelfApprovalsIgnoredTest.java b/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheckWithSelfApprovalsIgnoredTest.java
index a665ad4..43ab903 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheckWithSelfApprovalsIgnoredTest.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheckWithSelfApprovalsIgnoredTest.java
@@ -46,7 +46,7 @@
   /** Returns a {@code gerrit.config} that configures all users as fallback code owners. */
   @ConfigSuite.Default
   public static Config defaultConfig() {
-    Config cfg = new Config();
+    Config cfg = AbstractCodeOwnersTest.defaultConfig();
     cfg.setString(
         "plugin", "code-owners", OverrideApprovalConfig.KEY_OVERRIDE_APPROVAL, "Owners-Override+1");
     return cfg;
diff --git a/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheckWithStickyApprovalsTest.java b/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheckWithStickyApprovalsTest.java
index fc73235..28f83f5 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheckWithStickyApprovalsTest.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheckWithStickyApprovalsTest.java
@@ -55,7 +55,7 @@
   /** Returns a {@code gerrit.config} that configures all users as fallback code owners. */
   @ConfigSuite.Default
   public static Config defaultConfig() {
-    Config cfg = new Config();
+    Config cfg = AbstractCodeOwnersTest.defaultConfig();
     cfg.setBoolean(
         "plugin", "code-owners", GeneralConfig.KEY_ENABLE_STICKY_APPROVALS, /* value= */ true);
     return cfg;
diff --git a/javatests/com/google/gerrit/plugins/codeowners/backend/config/GeneralConfigTest.java b/javatests/com/google/gerrit/plugins/codeowners/backend/config/GeneralConfigTest.java
index 970aa74..17663b2 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/backend/config/GeneralConfigTest.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/backend/config/GeneralConfigTest.java
@@ -18,6 +18,7 @@
 import static com.google.gerrit.plugins.codeowners.backend.config.CodeOwnersPluginConfiguration.SECTION_CODE_OWNERS;
 import static com.google.gerrit.plugins.codeowners.backend.config.GeneralConfig.DEFAULT_MAX_PATHS_IN_CHANGE_MESSAGES;
 import static com.google.gerrit.plugins.codeowners.backend.config.GeneralConfig.KEY_ENABLE_ASYNC_MESSAGE_ON_ADD_REVIEWER;
+import static com.google.gerrit.plugins.codeowners.backend.config.GeneralConfig.KEY_ENABLE_ASYNC_MESSAGE_ON_CODE_OWNER_APPROVAL;
 import static com.google.gerrit.plugins.codeowners.backend.config.GeneralConfig.KEY_ENABLE_CODE_OWNER_CONFIG_FILES_WITH_FILE_EXTENSIONS;
 import static com.google.gerrit.plugins.codeowners.backend.config.GeneralConfig.KEY_ENABLE_IMPLICIT_APPROVALS;
 import static com.google.gerrit.plugins.codeowners.backend.config.GeneralConfig.KEY_ENABLE_STICKY_APPROVALS;
@@ -52,12 +53,19 @@
 import com.google.gerrit.plugins.codeowners.common.MergeCommitStrategy;
 import com.google.gerrit.server.git.validators.CommitValidationMessage;
 import com.google.gerrit.server.git.validators.ValidationMessage;
+import com.google.gerrit.testing.ConfigSuite;
 import org.eclipse.jgit.lib.Config;
 import org.junit.Before;
 import org.junit.Test;
 
 /** Tests for {@link com.google.gerrit.plugins.codeowners.backend.config.GeneralConfig}. */
 public class GeneralConfigTest extends AbstractCodeOwnersTest {
+  @ConfigSuite.Default
+  public static Config defaultConfig() {
+    // Override the settings from AbstractCodeOwnersTest.defaultConfig().
+    return new Config();
+  }
+
   private GeneralConfig generalConfig;
 
   @Before
@@ -2104,4 +2112,76 @@
       throws Exception {
     assertThat(generalConfig.enableAsyncMessageOnAddReviewer(project, new Config())).isTrue();
   }
+
+  @Test
+  public void cannotGetEnableAsyncMessageOnCodeOwnerApprovalForNullProject() throws Exception {
+    NullPointerException npe =
+        assertThrows(
+            NullPointerException.class,
+            () ->
+                generalConfig.enableAsyncMessageOnCodeOwnerApproval(
+                    /* project= */ null, new Config()));
+    assertThat(npe).hasMessageThat().isEqualTo("project");
+  }
+
+  @Test
+  public void cannotGetEnableAsyncMessageOnCodeOwnerApprovalForNullPluginConfig() throws Exception {
+    NullPointerException npe =
+        assertThrows(
+            NullPointerException.class,
+            () ->
+                generalConfig.enableAsyncMessageOnCodeOwnerApproval(
+                    project, /* pluginConfig= */ null));
+    assertThat(npe).hasMessageThat().isEqualTo("pluginConfig");
+  }
+
+  @Test
+  public void noEnableAsyncMessageOnCodeOwnerApproval() throws Exception {
+    assertThat(generalConfig.enableAsyncMessageOnCodeOwnerApproval(project, new Config())).isTrue();
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.enableAsyncMessageOnCodeOwnerApproval", value = "false")
+  public void
+      enableAsyncMessageOnCodeOwnerApprovalConfigurationIsRetrievedFromGerritConfigIfNotSpecifiedOnProjectLevel()
+          throws Exception {
+    assertThat(generalConfig.enableAsyncMessageOnCodeOwnerApproval(project, new Config()))
+        .isFalse();
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.enableAsyncMessageOnCodeOwnerApproval", value = "false")
+  public void
+      enableAsyncMessageOnCodeOwnerApprovalConfigurationInPluginConfigOverridesEnableAsyncMessageOnCodeOwnerApprovalConfigurationInGerritConfig()
+          throws Exception {
+    Config cfg = new Config();
+    cfg.setString(
+        SECTION_CODE_OWNERS,
+        /* subsection= */ null,
+        KEY_ENABLE_ASYNC_MESSAGE_ON_CODE_OWNER_APPROVAL,
+        "true");
+    assertThat(generalConfig.enableAsyncMessageOnCodeOwnerApproval(project, cfg)).isTrue();
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.enableAsyncMessageOnCodeOwnerApproval", value = "false")
+  public void invalidEnableAsyncMessageOnCodeOwnerApprovalConfigurationInPluginConfigIsIgnored()
+      throws Exception {
+    Config cfg = new Config();
+    cfg.setString(
+        SECTION_CODE_OWNERS,
+        /* subsection= */ null,
+        KEY_ENABLE_ASYNC_MESSAGE_ON_CODE_OWNER_APPROVAL,
+        "INVALID");
+    assertThat(generalConfig.enableAsyncMessageOnCodeOwnerApproval(project, cfg)).isFalse();
+  }
+
+  @Test
+  @GerritConfig(
+      name = "plugin.code-owners.enableAsyncMessageOnCodeOwnerApproval",
+      value = "INVALID")
+  public void invalidEnableAsyncMessageOnCodeOwnerApprovalConfigurationInGerritConfigIsIgnored()
+      throws Exception {
+    assertThat(generalConfig.enableAsyncMessageOnCodeOwnerApproval(project, new Config())).isTrue();
+  }
 }
diff --git a/resources/Documentation/config.md b/resources/Documentation/config.md
index 80c5b59..63feaf7 100644
--- a/resources/Documentation/config.md
+++ b/resources/Documentation/config.md
@@ -695,6 +695,22 @@
         in `@PLUGIN@.config`.\
         By default `true`.
 
+<a id="pluginCodeOwnersEnableAsyncMessageOnCodeOwnerApproval">plugin.@PLUGIN@.enableAsyncMessageOnCodeOwnerApproval</a>
+:       When a code owner approval is applied on a change the @PLUGIN@ plugin
+        posts a change message that lists the paths that are owned by the code
+        owner to inform that these paths are code owner approved now. This
+        setting controls whether this change message should be posted
+        asynchronously instead of synchronously extending the change message
+        that is posted for the approval by Gerrit core.\
+        Posting these change messages asynchronously improves the latency for
+        post review, since it does not need to wait until the owned paths are
+        computed for the code owner (computing the owned path for a user is
+        rather expensive).\
+        Can be overridden per project by setting
+        [codeOwners.enableAsyncMessageOnCodeOwnerApproval](#codeOwnersEnableAsyncMessageOnCodeOwnerApproval)
+        in `@PLUGIN@.config`.\
+        By default `true`.
+
 <a id="pluginCodeOwnersMaxCodeOwnerConfigCacheSize">plugin.@PLUGIN@.maxCodeOwnerConfigCacheSize</a>
 :       When computing code owner file statuses for a change (e.g. to compute
         the results for the code owners submit rule) parsed code owner config
@@ -1277,6 +1293,25 @@
         [plugin.@PLUGIN@.enableAsyncMessageOnAddReviewer](#pluginCodeOwnersEnableAsyncMessageOnAddReviewer)
         in `gerrit.config` is used.
 
+<a id="codeOwnersEnableAsyncMessageOnCodeOwnerApproval">codeOwners.enableAsyncMessageOnCodeOwnerApproval</a>
+:       When a code owner approval is applied on a change the @PLUGIN@ plugin
+        posts a change message that lists the paths that are owned by the code
+        owner to inform that these paths are code owner approved now. This
+        setting controls whether this change message should be posted
+        asynchronously instead of synchronously extending the change message
+        that is posted for the approval by Gerrit core.\
+        Posting these change messages asynchronously improves the latency for
+        post review, since it does not need to wait until the owned paths are
+        computed for the code owner (computing the owned path for a user is
+        rather expensive).\
+        Overrides the global setting
+        [plugin.@PLUGIN@.enableAsyncMessageOnCodeOwnerApproval](#pluginCodeOwnersEnableAsyncMessageOnOwnerApproval)
+        in `gerrit.config` and the `codeOwners.enableAsyncMessageOnCodeOwnerApproval`
+        setting from parent projects.\
+        If not set, the global setting
+        [plugin.@PLUGIN@.enableAsyncMessageOnCodeOwnerApproval](#pluginCodeOwnersEnableAsyncMessageOnCodeOwnerApproval)
+        in `gerrit.config` is used.
+
 ---
 
 Back to [@PLUGIN@ documentation index](index.html)
diff --git a/resources/Documentation/metrics.md b/resources/Documentation/metrics.md
index b5f7765..5a54abb 100644
--- a/resources/Documentation/metrics.md
+++ b/resources/Documentation/metrics.md
@@ -12,6 +12,9 @@
   added as a reviewer.
 ** `post_type':
    Whether the change message was posted synchronously or asynchronously.
+* `add_change_message_on_code_owner_approval`:
+  Latency for asynchronously adding a change message with the owned path when
+  a code owner approval is applied.
 * `compute_file_status`:
   Latency for computing the file status for one file.
 * `compute_file_statuses`:
@@ -25,8 +28,8 @@
 * `compute_patch_set_approvals`:
   Latency for computing the approvals of the current patch set.
 * `extend_change_message_on_post_review`:
-  Latency for extending the change message with the owned path when a code owner
-  approval is applied.
+  Latency for synchronously extending the change message with the owned path
+  when a code owner approval is applied.
 * `get_changed_files`:
   Latency for getting changed files from diff cache.
 * `prepare_file_status_computation`: