diff --git a/src/main/java/com/googlesource/gerrit/plugins/findowners/Cache.java b/src/main/java/com/googlesource/gerrit/plugins/findowners/Cache.java
index 7d4aa0c..48f86e6 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/findowners/Cache.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/findowners/Cache.java
@@ -17,6 +17,7 @@
 import static java.util.concurrent.TimeUnit.SECONDS;
 
 import com.google.common.cache.CacheBuilder;
+import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gwtorm.server.OrmException;
 import java.util.Collection;
@@ -90,17 +91,23 @@
 
   /** Returns a cached or new OwnersDb, for the specified patchset. */
   OwnersDb get(Repository repository, ChangeData changeData, int patchset) throws OrmException {
+    Project.NameKey project = changeData.change().getProject();
     String branch = changeData.change().getDest().get();
     String dbKey = Cache.makeKey(changeData.getId().get(), patchset, branch);
     // TODO: get changed files of the given patchset?
-    return get(dbKey, repository, branch, changeData.currentFilePaths());
+    return get(dbKey, repository, project, branch, changeData.currentFilePaths());
   }
 
   /** Returns a cached or new OwnersDb, for the specified branch and changed files. */
-  OwnersDb get(String key, Repository repository, String branch, Collection<String> files) {
+  OwnersDb get(
+      String key,
+      Repository repository,
+      Project.NameKey project,
+      String branch,
+      Collection<String> files) {
     if (dbCache == null) { // Do not cache OwnersDb
       log.trace("Create new OwnersDb, key=" + key);
-      return new OwnersDb(key, repository, branch, files);
+      return new OwnersDb(key, repository, project, branch, files);
     }
     try {
       log.trace("Get from cash " + dbCache + ", key=" + key + ", cache size=" + dbCache.size());
@@ -110,12 +117,12 @@
             @Override
             public OwnersDb call() {
               log.trace("Create new OwnersDb, key=" + key);
-              return new OwnersDb(key, repository, branch, files);
+              return new OwnersDb(key, repository, project, branch, files);
             }
           });
     } catch (ExecutionException e) {
       log.error("Cache.get has exception: " + e);
-      return new OwnersDb(key, repository, branch, files);
+      return new OwnersDb(key, repository, project, branch, files);
     }
   }
 
diff --git a/src/main/java/com/googlesource/gerrit/plugins/findowners/Config.java b/src/main/java/com/googlesource/gerrit/plugins/findowners/Config.java
index cdf9d56..d7008b3 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/findowners/Config.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/findowners/Config.java
@@ -26,17 +26,22 @@
 
 /** find-owners configuration parameters */
 class Config {
-  // Name of config parameters and plugin.
-  static final String SECTION = "findowners"; // used in Plugin config file
+  // Name of config parameters.
   static final String ADD_DEBUG_MSG = "addDebugMsg";
-  static final String MIN_OWNER_VOTE_LEVEL = "minOwnerVoteLevel";
+  static final String ALWAYS_SHOW_BUTTON = "alwaysShowButton"; // always show "Find Owners" button
   static final String MAX_CACHE_AGE = "maxCacheAge"; // seconds to stay in cache
   static final String MAX_CACHE_SIZE = "maxCacheSize"; // number of OwnersDb in cache
+  static final String MIN_OWNER_VOTE_LEVEL = "minOwnerVoteLevel"; // default +1
+  static final String OWNERS_FILE_NAME = "ownersFileName"; // default "OWNERS"
   static final String REPORT_SYNTAX_ERROR = "reportSyntaxError";
-  static final String ALWAYS_SHOW_BUTTON = "alwaysShowButton"; // always show "Find Owners" button
+
+  // Name of plugin and namespace.
   static final String PLUGIN_NAME = "find-owners";
   static final String PROLOG_NAMESPACE = "find_owners";
 
+  // Default values.
+  private static final String DEFAULT_OWNERS_FILE_NAME = "OWNERS";
+
   // Global/plugin config parameters.
   private static PluginConfigFactory config = null;
   private static boolean addDebugMsg = false;
@@ -83,6 +88,26 @@
     return alwaysShowButton;
   }
 
+  static String getOwnersFileName(Project.NameKey project) {
+    if (config != null && project != null) {
+      try {
+        String name =
+            config
+                .getFromProjectConfigWithInheritance(project, PLUGIN_NAME)
+                .getString(OWNERS_FILE_NAME, DEFAULT_OWNERS_FILE_NAME);
+        if (name.trim().equals("")) {
+          log.error(
+              "Project " + project.get() + " has wrong " + OWNERS_FILE_NAME + ": \"" + name + "\"");
+          return DEFAULT_OWNERS_FILE_NAME;
+        }
+        return name;
+      } catch (NoSuchProjectException e) {
+        log.error("Cannot find project: " + project);
+      }
+    }
+    return DEFAULT_OWNERS_FILE_NAME;
+  }
+
   @VisibleForTesting
   static void setReportSyntaxError(boolean value) {
     reportSyntaxError = value;
diff --git a/src/main/java/com/googlesource/gerrit/plugins/findowners/OwnersDb.java b/src/main/java/com/googlesource/gerrit/plugins/findowners/OwnersDb.java
index 04a087a..b2ce1f9 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/findowners/OwnersDb.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/findowners/OwnersDb.java
@@ -16,6 +16,7 @@
 
 import static java.nio.charset.StandardCharsets.UTF_8;
 
+import com.google.gerrit.reviewdb.client.Project;
 import java.io.IOException;
 import java.nio.file.FileSystem;
 import java.nio.file.FileSystems;
@@ -51,8 +52,14 @@
 
   OwnersDb() {}
 
-  OwnersDb(String key, Repository repository, String branch, Collection<String> files) {
+  OwnersDb(
+      String key,
+      Repository repository,
+      Project.NameKey project,
+      String branch,
+      Collection<String> files) {
     this.key = key;
+    String ownersFileName = Config.getOwnersFileName(project);
     for (String fileName : files) {
       // Find OWNERS in fileName's directory and parent directories.
       // Stop looking for a parent directory if OWNERS has "set noparent".
@@ -60,10 +67,10 @@
       String dir = Util.normalizedDirPath(fileName); // e.g. dir = ./d1/d2
       while (!readDirs.contains(dir)) {
         readDirs.add(dir);
-        String filePath = (dir + "/OWNERS").substring(2); // remove "./"
+        String filePath = (dir + "/" + ownersFileName).substring(2); // remove "./"
         String content = getRepositoryFile(repository, branch, filePath);
         if (content != null && !content.equals("")) {
-          addFile(dir + "/", dir + "/OWNERS", content.split("\\R+"));
+          addFile(dir + "/", dir + "/" + ownersFileName, content.split("\\R+"));
         }
         if (stopLooking.contains(dir + "/") || !dir.contains("/")) {
           break; // stop looking through parent directory
diff --git a/src/main/resources/Documentation/config.md b/src/main/resources/Documentation/config.md
index 91dfea0..d754912 100644
--- a/src/main/resources/Documentation/config.md
+++ b/src/main/resources/Documentation/config.md
@@ -61,6 +61,12 @@
 are applied, the default requirement is **+1** Code-Review
 vote from at least one owner of every changed file.
 
+## Default OWNERS file name
+
+This plugin finds owners in default OWNERS files.
+If a project has already used OWNERS files for other purpose,
+the "ownersFileName" parameter can be used to change the default.
+
 ## Example 0, call `submit_filter/2`
 
 The simplest configuration adds to `rules.pl` of the root
@@ -135,11 +141,22 @@
 
 ## Example 6, define `addDebugMsg`
 
-Add the following to global `gerrit.config`
-or a project's `project.config` file,
+Add the following to global `gerrit.config`,
 to debug the find-owners plugin.
 
 ```bash
 [plugin "find-owners"]
     addDebugMsg = true
 ```
+
+## Example 7, change default OWNERS file name
+
+Add the following to global `gerrit.config`
+or a project's `project.config` file,
+to change the default "OWNERS" file name,
+e.g., to "OWNERS.android".
+
+```bash
+[plugin "find-owners"]
+    ownersFileName = OWNERS.android
+```
diff --git a/src/test/java/com/googlesource/gerrit/plugins/findowners/FindOwnersIT.java b/src/test/java/com/googlesource/gerrit/plugins/findowners/FindOwnersIT.java
index 1501b3e..c8b3b3e 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/findowners/FindOwnersIT.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/findowners/FindOwnersIT.java
@@ -15,6 +15,8 @@
 package com.googlesource.gerrit.plugins.findowners;
 
 import static com.google.common.truth.Truth.assertThat;
+import static com.google.gerrit.reviewdb.client.RefNames.REFS_CONFIG;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.gerrit.acceptance.LightweightPluginDaemonTest;
 import com.google.gerrit.acceptance.PushOneCommit;
@@ -26,13 +28,24 @@
 import com.google.gerrit.extensions.common.ChangeInput;
 import com.google.gerrit.extensions.restapi.Response;
 import com.google.gerrit.reviewdb.client.Account;
+import com.google.gerrit.reviewdb.client.Project;
+import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.server.change.ChangeResource;
+import com.google.gerrit.server.config.PluginConfigFactory;
+import com.google.inject.Inject;
+import org.eclipse.jgit.lib.ObjectLoader;
+import org.eclipse.jgit.revwalk.RevObject;
+import org.eclipse.jgit.revwalk.RevTree;
+import org.eclipse.jgit.revwalk.RevWalk;
+import org.eclipse.jgit.transport.RefSpec;
 import org.junit.Test;
 
 /** Test find-owners plugin API. */
 @TestPlugin(name = "find-owners", sysModule = "com.googlesource.gerrit.plugins.findowners.Module")
 public class FindOwnersIT extends LightweightPluginDaemonTest {
 
+  @Inject private PluginConfigFactory configFactory;
+
   @Test
   public void getOwnersTest() throws Exception {
     ChangeInfo info1 = newChangeInfo("test1 GetOwners");
@@ -171,6 +184,71 @@
   }
 
   @Test
+  public void ownersFileNameTest() throws Exception {
+    Config.setVariables("find-owners", configFactory);
+
+    // Default project is something like ....FindOwnersIT..._project
+    Project.NameKey pA = createProject("Project_A");
+    Project.NameKey pB = createProject("Project_B");
+    switchProject(pA);
+    // Now project is ....FindOwnersIT..._Project_A
+    switchProject(pB);
+    // Now project is ....FindOwnersIT..._Project_B
+
+    // Add OWNERS and OWNERS.alpha file to Project_A.
+    switchProject(pA);
+    addFile("add OWNERS", "OWNERS", "per-file *.c=x@x\n"); // default owner x@x
+    addFile("add OWNERS.alpha", "OWNERS.alpha", "per-file *.c=a@a\n"); // alpha owner a@a
+    PushOneCommit.Result cA = createChange("add tA.c", "tA.c", "Hello A!");
+
+    // Add OWNERS and OWNERS.beta file to Project_B.
+    switchProject(pB);
+    addFile("add OWNERS", "OWNERS", "per-file *.c=y@y\n"); // default owner y@y
+    addFile("add OWNERS.beta", "OWNERS.beta", "per-file *.c=b@b\n"); // beta owner b@b
+    PushOneCommit.Result cB = createChange("add tB.c", "tB.c", "Hello B!");
+
+    // Default owners file name is "OWNERS".
+    assertThat(Config.getOwnersFileName(null)).isEqualTo("OWNERS");
+    assertThat(Config.getOwnersFileName(pA)).isEqualTo("OWNERS");
+    assertThat(Config.getOwnersFileName(pB)).isEqualTo("OWNERS");
+
+    assertThat(getOwnersResponse(cA)).contains("owners:[ x@x[1+0+0] ], files:[ tA.c ]");
+    assertThat(getOwnersResponse(cB)).contains("owners:[ y@y[1+0+0] ], files:[ tB.c ]");
+
+    // Change owners file name to "OWNERS.alpha" and "OWNERS.beta"
+    switchProject(pA);
+    setProjectConfig("ownersFileName", "OWNERS.alpha");
+    switchProject(pB);
+    setProjectConfig("ownersFileName", "OWNERS.beta");
+    assertThat(Config.getOwnersFileName(pA)).isEqualTo("OWNERS.alpha");
+    assertThat(Config.getOwnersFileName(pB)).isEqualTo("OWNERS.beta");
+    assertThat(getOwnersResponse(cA)).contains("owners:[ a@a[1+0+0] ], files:[ tA.c ]");
+    assertThat(getOwnersResponse(cB)).contains("owners:[ b@b[1+0+0] ], files:[ tB.c ]");
+
+    // Change back to OWNERS in Project_A
+    switchProject(pA);
+    setProjectConfig("ownersFileName", "OWNERS");
+    assertThat(Config.getOwnersFileName(pA)).isEqualTo("OWNERS");
+    assertThat(getOwnersResponse(cA)).contains("owners:[ x@x[1+0+0] ], files:[ tA.c ]");
+    assertThat(getOwnersResponse(cB)).contains("owners:[ b@b[1+0+0] ], files:[ tB.c ]");
+
+    // Change back to OWNERS.alpha in Project_B, but there is no OWNERS.alpha
+    switchProject(pB);
+    setProjectConfig("ownersFileName", "OWNERS.alpha");
+    assertThat(Config.getOwnersFileName(pB)).isEqualTo("OWNERS.alpha");
+    assertThat(getOwnersResponse(cA)).contains("owners:[ x@x[1+0+0] ], files:[ tA.c ]");
+    assertThat(getOwnersResponse(cB)).contains("owners:[], files:[ tB.c ]");
+
+    // Do not accept empty string or all-white-spaces for ownersFileName.
+    setProjectConfig("ownersFileName", "   ");
+    assertThat(Config.getOwnersFileName(pB)).isEqualTo("OWNERS");
+    setProjectConfig("ownersFileName", " \t  ");
+    assertThat(Config.getOwnersFileName(pB)).isEqualTo("OWNERS");
+    setProjectConfig("ownersFileName", "O");
+    assertThat(Config.getOwnersFileName(pB)).isEqualTo("O");
+  }
+
+  @Test
   public void actionApplyTest() throws Exception {
     Cache cache = Cache.getInstance().init(0, 10);
     assertThat(cache.size()).isEqualTo(0);
@@ -239,6 +317,42 @@
     approveSubmit(createChange(subject, file, content));
   }
 
+  private void switchProject(Project.NameKey p) throws Exception {
+    project = p;
+    testRepo = cloneProject(project);
+  }
+
+  private org.eclipse.jgit.lib.Config readProjectConfig() throws Exception {
+    git().fetch().setRefSpecs(new RefSpec(REFS_CONFIG + ":" + REFS_CONFIG)).call();
+    testRepo.reset(RefNames.REFS_CONFIG);
+    RevWalk rw = testRepo.getRevWalk();
+    RevTree tree = rw.parseTree(testRepo.getRepository().resolve("HEAD"));
+    RevObject obj = rw.parseAny(testRepo.get(tree, "project.config"));
+    ObjectLoader loader = rw.getObjectReader().open(obj);
+    String text = new String(loader.getCachedBytes(), UTF_8);
+    org.eclipse.jgit.lib.Config cfg = new org.eclipse.jgit.lib.Config();
+    cfg.fromText(text);
+    return cfg;
+  }
+
+  private void setProjectConfig(String var, String value) throws Exception {
+    org.eclipse.jgit.lib.Config cfg = readProjectConfig();
+    cfg.setString("plugin", "find-owners", var, value);
+    assertThat(cfg.getString("plugin", "find-owners", var)).isEqualTo(value);
+    PushOneCommit.Result commit =
+        pushFactory
+            .create(
+                db,
+                admin.getIdent(), // normal user cannot change refs/meta/config
+                testRepo,
+                "Update project config",
+                "project.config",
+                cfg.toText())
+            .to("refs/for/" + REFS_CONFIG);
+    commit.assertOkStatus();
+    approveSubmit(commit);
+  }
+
   // Remove '"' and space; replace '\n' with ' '; ignore unpredictable "owner_revision".
   private static String filteredJson(String json) {
     return json.replaceAll("[\" ]*", "").replace('\n', ' ').replaceAll("owner_revision:[^ ]* ", "");