diff --git a/java/com/google/gerrit/plugins/codeowners/backend/ChangedFiles.java b/java/com/google/gerrit/plugins/codeowners/backend/ChangedFiles.java
index c96af17..b691e21 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/ChangedFiles.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/ChangedFiles.java
@@ -15,10 +15,10 @@
 package com.google.gerrit.plugins.codeowners.backend;
 
 import static com.google.common.base.Preconditions.checkState;
-import static com.google.common.collect.ImmutableSet.toImmutableSet;
+import static com.google.common.collect.ImmutableList.toImmutableList;
 import static java.util.Objects.requireNonNull;
 
-import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.ImmutableList;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.entities.Patch;
 import com.google.gerrit.entities.Project;
@@ -84,12 +84,12 @@
    * <p>The diff is computed against the parent commit.
    *
    * @param revisionResource the revision resource for which the changed files should be computed
-   * @return the files that have been changed in the given revision
+   * @return the files that have been changed in the given revision, sorted alphabetically by path
    * @throws IOException thrown if the computation fails due to an I/O error
    * @throws PatchListNotAvailableException thrown if getting the patch list for a merge commit
    *     against the auto merge failed
    */
-  public ImmutableSet<ChangedFile> compute(RevisionResource revisionResource)
+  public ImmutableList<ChangedFile> compute(RevisionResource revisionResource)
       throws IOException, PatchListNotAvailableException {
     requireNonNull(revisionResource, "revisionResource");
     return compute(revisionResource.getProject(), revisionResource.getPatchSet().commitId());
@@ -102,12 +102,12 @@
    *
    * @param project the project
    * @param revision the revision for which the changed files should be computed
-   * @return the files that have been changed in the given revision
+   * @return the files that have been changed in the given revision, sorted alphabetically by path
    * @throws IOException thrown if the computation fails due to an I/O error
    * @throws PatchListNotAvailableException thrown if getting the patch list for a merge commit
    *     against the auto merge failed
    */
-  public ImmutableSet<ChangedFile> compute(Project.NameKey project, ObjectId revision)
+  public ImmutableList<ChangedFile> compute(Project.NameKey project, ObjectId revision)
       throws IOException, PatchListNotAvailableException {
     requireNonNull(project, "project");
     requireNonNull(revision, "revision");
@@ -119,7 +119,7 @@
     }
   }
 
-  public ImmutableSet<ChangedFile> compute(
+  public ImmutableList<ChangedFile> compute(
       Project.NameKey project, Config repoConfig, RevWalk revWalk, RevCommit revCommit)
       throws IOException, PatchListNotAvailableException {
     return compute(
@@ -130,7 +130,7 @@
         codeOwnersPluginConfiguration.getProjectConfig(project).getMergeCommitStrategy());
   }
 
-  public ImmutableSet<ChangedFile> compute(
+  public ImmutableList<ChangedFile> compute(
       Project.NameKey project,
       Config repoConfig,
       RevWalk revWalk,
@@ -164,7 +164,7 @@
    * @param mergeCommit the merge commit for which the changed files should be computed
    * @return the changed files for the given merge commit
    */
-  private ImmutableSet<ChangedFile> computeByComparingAgainstAutoMerge(
+  private ImmutableList<ChangedFile> computeByComparingAgainstAutoMerge(
       Project.NameKey project, RevCommit mergeCommit) throws PatchListNotAvailableException {
     checkState(
         mergeCommit.getParentCount() > 1, "expected %s to be a merge commit", mergeCommit.name());
@@ -180,7 +180,7 @@
                   patchListEntry.getNewName() == null
                       || !Patch.isMagic(patchListEntry.getNewName()))
           .map(ChangedFile::create)
-          .collect(toImmutableSet());
+          .collect(toImmutableList());
     }
   }
 
@@ -192,9 +192,9 @@
    * @param repoConfig the repository configuration
    * @param revWalk the rev walk
    * @param revCommit the commit for which the changed files should be computed
-   * @return the changed files for the given commit
+   * @return the changed files for the given commit, sorted alphabetically by path
    */
-  private ImmutableSet<ChangedFile> computeByComparingAgainstFirstParent(
+  private ImmutableList<ChangedFile> computeByComparingAgainstFirstParent(
       Config repoConfig, RevWalk revWalk, RevCommit revCommit) throws IOException {
     try (Timer0.Context ctx = codeOwnerMetrics.computeChangedFilesAgainstFirstParent.start()) {
       RevCommit baseCommit = revCommit.getParentCount() > 0 ? revCommit.getParent(0) : null;
@@ -209,8 +209,8 @@
         diffFormatter.setReader(revWalk.getObjectReader(), repoConfig);
         diffFormatter.setDiffComparator(RawTextComparator.DEFAULT);
         List<DiffEntry> diffEntries = diffFormatter.scan(baseCommit, revCommit);
-        ImmutableSet<ChangedFile> changedFiles =
-            diffEntries.stream().map(ChangedFile::create).collect(toImmutableSet());
+        ImmutableList<ChangedFile> changedFiles =
+            diffEntries.stream().map(ChangedFile::create).collect(toImmutableList());
         if (changedFiles.size() <= MAX_CHANGED_FILES_TO_LOG) {
           logger.atFine().log("changed files = %s", changedFiles);
         } else {
diff --git a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheck.java b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheck.java
index 1c5e87f..5ab28b4 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheck.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnerApprovalCheck.java
@@ -17,7 +17,6 @@
 import static com.google.common.base.Preconditions.checkState;
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
-import static java.util.Comparator.comparing;
 import static java.util.Objects.requireNonNull;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -149,8 +148,7 @@
                           .map(Optional::get))
               .filter(
                   pathCodeOwnerStatus -> pathCodeOwnerStatus.status() == CodeOwnerStatus.APPROVED)
-              .map(PathCodeOwnerStatus::path)
-              .sorted(comparing(Path::toString));
+              .map(PathCodeOwnerStatus::path);
       if (limit > 0) {
         ownedPaths = ownedPaths.limit(limit);
       }
diff --git a/java/com/google/gerrit/plugins/codeowners/testing/BUILD b/java/com/google/gerrit/plugins/codeowners/testing/BUILD
index cff6196..16af5f4 100644
--- a/java/com/google/gerrit/plugins/codeowners/testing/BUILD
+++ b/java/com/google/gerrit/plugins/codeowners/testing/BUILD
@@ -19,5 +19,6 @@
         "//plugins/code-owners/java/com/google/gerrit/plugins/codeowners/backend",
         "//plugins/code-owners/java/com/google/gerrit/plugins/codeowners/common",
         "//plugins/code-owners/java/com/google/gerrit/plugins/codeowners/restapi",
+        "//plugins/code-owners/java/com/google/gerrit/plugins/codeowners/util",
     ],
 )
diff --git a/java/com/google/gerrit/plugins/codeowners/testing/ChangedFileSubject.java b/java/com/google/gerrit/plugins/codeowners/testing/ChangedFileSubject.java
index 069122c..9484c97 100644
--- a/java/com/google/gerrit/plugins/codeowners/testing/ChangedFileSubject.java
+++ b/java/com/google/gerrit/plugins/codeowners/testing/ChangedFileSubject.java
@@ -18,16 +18,34 @@
 import static com.google.gerrit.truth.OptionalSubject.optionals;
 
 import com.google.common.collect.ImmutableList;
+import com.google.common.truth.Correspondence;
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
 import com.google.gerrit.plugins.codeowners.common.ChangedFile;
+import com.google.gerrit.plugins.codeowners.util.JgitPath;
 import com.google.gerrit.truth.ListSubject;
+import com.google.gerrit.truth.NullAwareCorrespondence;
 import com.google.gerrit.truth.OptionalSubject;
 import java.util.Collection;
 
 /** {@link Subject} for doing assertions on {@link ChangedFile}s. */
 public class ChangedFileSubject extends Subject {
   /**
+   * Constructs a {@link Correspondence} that maps {@link ChangedFile}s to their paths (new path if
+   * set, otherwise old path).
+   */
+  public static Correspondence<ChangedFile, String> hasPath() {
+    return NullAwareCorrespondence.transforming(
+        changedFile ->
+            JgitPath.of(
+                    changedFile.newPath().isPresent()
+                        ? changedFile.newPath().get()
+                        : changedFile.oldPath().get())
+                .get(),
+        "has path");
+  }
+
+  /**
    * Starts fluent chain to do assertions on a {@link ChangedFile}.
    *
    * @param changedFile the changed file on which assertions should be done
diff --git a/javatests/com/google/gerrit/plugins/codeowners/backend/ChangedFilesTest.java b/javatests/com/google/gerrit/plugins/codeowners/backend/ChangedFilesTest.java
index 34e0cb2..2bbc4f4 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/backend/ChangedFilesTest.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/backend/ChangedFilesTest.java
@@ -18,9 +18,12 @@
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.gerrit.plugins.codeowners.testing.ChangedFileSubject.assertThat;
 import static com.google.gerrit.plugins.codeowners.testing.ChangedFileSubject.assertThatCollection;
+import static com.google.gerrit.plugins.codeowners.testing.ChangedFileSubject.hasPath;
 import static com.google.gerrit.testing.GerritJUnit.assertThrows;
 import static org.junit.Assert.fail;
 
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
 import com.google.gerrit.acceptance.PushOneCommit;
@@ -88,7 +91,8 @@
     String changeId =
         createChange("Change Adding A File", JgitPath.of(path).get(), "file content").getChangeId();
 
-    ImmutableSet<ChangedFile> changedFilesSet = changedFiles.compute(getRevisionResource(changeId));
+    ImmutableList<ChangedFile> changedFilesSet =
+        changedFiles.compute(getRevisionResource(changeId));
     assertThat(changedFilesSet).hasSize(1);
     ChangedFile changedFile = Iterables.getOnlyElement(changedFilesSet);
     assertThat(changedFile).hasNewPath().value().isEqualTo(Paths.get(path));
@@ -106,7 +110,8 @@
         createChange("Change Modifying A File", JgitPath.of(path).get(), "new file content")
             .getChangeId();
 
-    ImmutableSet<ChangedFile> changedFilesSet = changedFiles.compute(getRevisionResource(changeId));
+    ImmutableList<ChangedFile> changedFilesSet =
+        changedFiles.compute(getRevisionResource(changeId));
     assertThat(changedFilesSet).hasSize(1);
     ChangedFile changedFile = Iterables.getOnlyElement(changedFilesSet);
     assertThat(changedFile).hasNewPath().value().isEqualTo(Paths.get(path));
@@ -120,7 +125,8 @@
     String path = "/foo/bar/baz.txt";
     String changeId = createChangeWithFileDeletion(path);
 
-    ImmutableSet<ChangedFile> changedFilesSet = changedFiles.compute(getRevisionResource(changeId));
+    ImmutableList<ChangedFile> changedFilesSet =
+        changedFiles.compute(getRevisionResource(changeId));
     assertThat(changedFilesSet).hasSize(1);
     ChangedFile changedFile = Iterables.getOnlyElement(changedFilesSet);
     assertThat(changedFile).hasNewPath().isEmpty();
@@ -140,7 +146,8 @@
     // A renamed file is reported as addition of new path + deletion of old path. This is because
     // ChangedFiles uses a DiffFormatter without rename detection (because rename detection requires
     // loading the file contents which is too expensive).
-    ImmutableSet<ChangedFile> changedFilesSet = changedFiles.compute(getRevisionResource(changeId));
+    ImmutableList<ChangedFile> changedFilesSet =
+        changedFiles.compute(getRevisionResource(changeId));
     assertThat(changedFilesSet).hasSize(2);
     ChangedFileSubject changedFile1 = assertThatCollection(changedFilesSet).element(0);
     changedFile1.hasNewPath().value().isEqualTo(Paths.get(newPath));
@@ -162,7 +169,8 @@
     assertThat(r.getCommit().getParents()).isEmpty();
     String changeId = r.getChangeId();
 
-    ImmutableSet<ChangedFile> changedFilesSet = changedFiles.compute(getRevisionResource(changeId));
+    ImmutableList<ChangedFile> changedFilesSet =
+        changedFiles.compute(getRevisionResource(changeId));
     assertThat(changedFilesSet).hasSize(1);
     ChangedFile changedFile = Iterables.getOnlyElement(changedFilesSet);
     assertThat(changedFile).hasNewPath().value().isEqualTo(Paths.get(path));
@@ -241,17 +249,13 @@
             .content("content")
             .create();
 
-    ImmutableSet<ChangedFile> changedFilesSet =
+    ImmutableList<ChangedFile> changedFilesSet =
         changedFiles.compute(getRevisionResource(Integer.toString(mergeChange.get())));
-    ImmutableSet<String> paths =
-        changedFilesSet.stream()
-            .map(changedFile -> JgitPath.of(changedFile.newPath().get()).get())
-            .collect(toImmutableSet());
 
     if (MergeCommitStrategy.ALL_CHANGED_FILES.equals(mergeCommitStrategy)) {
-      assertThat(paths).containsExactly(file1, file2);
+      assertThat(changedFilesSet).comparingElementsUsing(hasPath()).containsExactly(file1, file2);
     } else if (MergeCommitStrategy.FILES_WITH_CONFLICT_RESOLUTION.equals(mergeCommitStrategy)) {
-      assertThat(paths).containsExactly(file1);
+      assertThat(changedFilesSet).comparingElementsUsing(hasPath()).containsExactly(file1);
     } else {
       fail("expected merge commit strategy: " + mergeCommitStrategy);
     }
@@ -318,7 +322,7 @@
             .delete()
             .create();
 
-    ImmutableSet<ChangedFile> changedFilesSet =
+    ImmutableList<ChangedFile> changedFilesSet =
         changedFiles.compute(getRevisionResource(Integer.toString(mergeChange.get())));
     ImmutableSet<String> oldPaths =
         changedFilesSet.stream()
@@ -327,6 +331,153 @@
     assertThat(oldPaths).containsExactly(file);
   }
 
+  @Test
+  public void sortedByPath() throws Exception {
+    String file1 = "foo/bar.baz";
+    String file2 = "foo/baz.bar";
+    String file3 = "bar/foo.baz";
+    String file4 = "bar/baz.foo";
+    String file5 = "baz/foo.bar";
+    String changeId =
+        createChange(
+                "Test Change",
+                ImmutableMap.of(
+                    file1,
+                    "file content",
+                    file2,
+                    "file content",
+                    file3,
+                    "file content",
+                    file4,
+                    "file content",
+                    file5,
+                    "file content"))
+            .getChangeId();
+
+    ImmutableList<ChangedFile> changedFilesSet =
+        changedFiles.compute(getRevisionResource(changeId));
+    assertThat(changedFilesSet)
+        .comparingElementsUsing(hasPath())
+        .containsExactly(file4, file3, file5, file1, file2)
+        .inOrder();
+  }
+
+  @Test
+  @GerritConfig(name = "plugin.code-owners.mergeCommitStrategy", value = "ALL_CHANGED_FILES")
+  public void sortedByPath_mergeCommitAgainstFirstParent() throws Exception {
+    testSortedByPathForMerge(MergeCommitStrategy.ALL_CHANGED_FILES);
+  }
+
+  @Test
+  @GerritConfig(
+      name = "plugin.code-owners.mergeCommitStrategy",
+      value = "FILES_WITH_CONFLICT_RESOLUTION")
+  public void sortedByPath_mergeCommitAgainstAutoMerge() throws Exception {
+    testSortedByPathForMerge(MergeCommitStrategy.FILES_WITH_CONFLICT_RESOLUTION);
+  }
+
+  private void testSortedByPathForMerge(MergeCommitStrategy mergeCommitStrategy) throws Exception {
+    setAsRootCodeOwners(admin);
+
+    String file1 = "foo/bar.baz";
+    String file2 = "foo/baz.bar";
+    String file3 = "bar/foo.baz";
+    String file4 = "bar/baz.foo";
+    String file5 = "baz/foo.bar";
+
+    // Create a base change.
+    Change.Id baseChange =
+        changeOperations
+            .newChange()
+            .branch("master")
+            .file(file1)
+            .content("base content")
+            .file(file3)
+            .content("base content")
+            .file(file5)
+            .content("base content")
+            .create();
+    approveAndSubmit(baseChange);
+
+    // Create another branch
+    String branchName = "foo";
+    BranchInput branchInput = new BranchInput();
+    branchInput.ref = branchName;
+    branchInput.revision = projectOperations.project(project).getHead("master").name();
+    gApi.projects().name(project.get()).branch(branchInput.ref).create(branchInput);
+
+    // Create a change in master that touches file1, file3 and file5
+    Change.Id changeInMaster =
+        changeOperations
+            .newChange()
+            .branch("master")
+            .file(file1)
+            .content("master content")
+            .file(file3)
+            .content("master content")
+            .file(file5)
+            .content("master content")
+            .create();
+    approveAndSubmit(changeInMaster);
+
+    // Create a change in the other branch and that touches file1, file3, file5 and creates file2,
+    // file4.
+    Change.Id changeInOtherBranch =
+        changeOperations
+            .newChange()
+            .branch(branchName)
+            .file(file1)
+            .content("other content")
+            .file(file2)
+            .content("content")
+            .file(file3)
+            .content("other content")
+            .file(file4)
+            .content("content")
+            .file(file5)
+            .content("other content")
+            .create();
+    approveAndSubmit(changeInOtherBranch);
+
+    // Create a merge change with a conflict resolution for file1 and file2 with the same content as
+    // in the other branch (no conflict on file2).
+    Change.Id mergeChange =
+        changeOperations
+            .newChange()
+            .branch("master")
+            .mergeOfButBaseOnFirst()
+            .tipOfBranch("master")
+            .and()
+            .tipOfBranch(branchName)
+            .file(file1)
+            .content("merged content")
+            .file(file2)
+            .content("content")
+            .file(file3)
+            .content("merged content")
+            .file(file4)
+            .content("content")
+            .file(file5)
+            .content("merged content")
+            .create();
+
+    ImmutableList<ChangedFile> changedFilesSet =
+        changedFiles.compute(getRevisionResource(Integer.toString(mergeChange.get())));
+
+    if (MergeCommitStrategy.ALL_CHANGED_FILES.equals(mergeCommitStrategy)) {
+      assertThat(changedFilesSet)
+          .comparingElementsUsing(hasPath())
+          .containsExactly(file4, file3, file5, file1, file2)
+          .inOrder();
+    } else if (MergeCommitStrategy.FILES_WITH_CONFLICT_RESOLUTION.equals(mergeCommitStrategy)) {
+      assertThat(changedFilesSet)
+          .comparingElementsUsing(hasPath())
+          .containsExactly(file3, file5, file1);
+    } else {
+      fail("expected merge commit strategy: " + mergeCommitStrategy);
+    }
+  }
+
   private void approveAndSubmit(Change.Id changeId) throws Exception {
     approve(Integer.toString(changeId.get()));
     gApi.changes().id(changeId.get()).current().submit();