diff --git a/src/main/java/com/englishtown/bitbucket/hook/MirrorRepositoryHook.java b/src/main/java/com/englishtown/bitbucket/hook/MirrorRepositoryHook.java
index 3c82205..643904d 100644
--- a/src/main/java/com/englishtown/bitbucket/hook/MirrorRepositoryHook.java
+++ b/src/main/java/com/englishtown/bitbucket/hook/MirrorRepositoryHook.java
@@ -4,9 +4,7 @@ import com.atlassian.bitbucket.concurrent.BucketedExecutor;
 import com.atlassian.bitbucket.concurrent.BucketedExecutorSettings;
 import com.atlassian.bitbucket.concurrent.ConcurrencyPolicy;
 import com.atlassian.bitbucket.concurrent.ConcurrencyService;
-import com.atlassian.bitbucket.hook.repository.PostRepositoryHook;
-import com.atlassian.bitbucket.hook.repository.PostRepositoryHookContext;
-import com.atlassian.bitbucket.hook.repository.RepositoryHookRequest;
+import com.atlassian.bitbucket.hook.repository.*;
 import com.atlassian.bitbucket.repository.Repository;
 import com.atlassian.bitbucket.scm.git.GitScm;
 import com.atlassian.bitbucket.scope.RepositoryScope;
@@ -16,15 +14,13 @@ import com.atlassian.bitbucket.server.ApplicationPropertiesService;
 import com.atlassian.bitbucket.setting.Settings;
 import com.atlassian.bitbucket.setting.SettingsValidationErrors;
 import com.atlassian.bitbucket.setting.SettingsValidator;
+import com.google.common.collect.ImmutableSet;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import javax.annotation.Nonnull;
 import java.net.URI;
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 import java.util.concurrent.TimeUnit;
 
 public class MirrorRepositoryHook implements PostRepositoryHook<RepositoryHookRequest>, SettingsValidator {
@@ -40,6 +36,14 @@ public class MirrorRepositoryHook implements PostRepositoryHook<RepositoryHookRe
     static final String SETTING_NOTES = "notes";
     static final String SETTING_ATOMIC = "atomic";
 
+    /**
+     * Trigger types that don't cause a mirror to happen
+     */
+    private static Set<RepositoryHookTrigger> TRIGGERS_TO_IGNORE =
+            ImmutableSet.of(
+                    StandardRepositoryHookTrigger.UNKNOWN
+            );
+
     private final PasswordEncryptor passwordEncryptor;
     private final SettingsReflectionHelper settingsReflectionHelper;
     private final BucketedExecutor<MirrorRequest> pushExecutor;
@@ -72,11 +76,16 @@ public class MirrorRepositoryHook implements PostRepositoryHook<RepositoryHookRe
     /**
      * Schedules pushes to apply the latest changes to any configured mirrors.
      *
-     * @param context provides any settings which have been configured for the hook
-     * @param request describes the repository and refs which were updated
+     * @param context provides hook settings and a way to obtain the commits added/removed
+     * @param request provides details about the refs that have been updated
      */
     @Override
     public void postUpdate(@Nonnull PostRepositoryHookContext context, @Nonnull RepositoryHookRequest request) {
+        if (TRIGGERS_TO_IGNORE.contains(request.getTrigger())) {
+            logger.trace("MirrorRepositoryHook: skipping trigger {}", request.getTrigger());
+            return;
+        }
+
         Repository repository = request.getRepository();
         if (!GitScm.ID.equalsIgnoreCase(repository.getScmId())) {
             return;
@@ -93,11 +102,11 @@ public class MirrorRepositoryHook implements PostRepositoryHook<RepositoryHookRe
     }
 
     /**
-     * Validates hook settings before they are persisted, and encrypts any user-supplied password.
+     * Validate the given {@code settings} before they are persisted., and encrypts any user-supplied password.
      *
      * @param settings to be validated
-     * @param errors   callback for reporting validation errors
-     * @param scope    the scope for which the hook has been configured
+     * @param errors   callback for reporting validation errors.
+     * @param scope    the context {@code Repository} the settings will be associated with
      */
     @Override
     public void validate(@Nonnull Settings settings, @Nonnull SettingsValidationErrors errors, @Nonnull Scope scope) {
diff --git a/src/test/java/com/englishtown/bitbucket/hook/MirrorRepositoryHookTest.java b/src/test/java/com/englishtown/bitbucket/hook/MirrorRepositoryHookTest.java
index cc2cf43..19ec275 100644
--- a/src/test/java/com/englishtown/bitbucket/hook/MirrorRepositoryHookTest.java
+++ b/src/test/java/com/englishtown/bitbucket/hook/MirrorRepositoryHookTest.java
@@ -2,8 +2,7 @@ package com.englishtown.bitbucket.hook;
 
 import com.atlassian.bitbucket.concurrent.BucketedExecutor;
 import com.atlassian.bitbucket.concurrent.ConcurrencyService;
-import com.atlassian.bitbucket.hook.repository.PostRepositoryHookContext;
-import com.atlassian.bitbucket.hook.repository.RepositoryPushHookRequest;
+import com.atlassian.bitbucket.hook.repository.*;
 import com.atlassian.bitbucket.project.Project;
 import com.atlassian.bitbucket.repository.Repository;
 import com.atlassian.bitbucket.scm.git.GitScm;
@@ -24,7 +23,6 @@ import org.mockito.junit.MockitoRule;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.Set;
 import java.util.concurrent.TimeUnit;
 
 import static com.atlassian.bitbucket.mockito.MockitoUtils.returnArg;
@@ -118,6 +116,15 @@ public class MirrorRepositoryHookTest {
         verifyZeroInteractions(bucketedExecutor);
     }
 
+    @Test
+    public void testUnwantedEventsIgnored() {
+        Repository repo = mock(Repository.class);
+
+        hook.postUpdate(buildContext(), buildRequest(StandardRepositoryHookTrigger.UNKNOWN, repo));
+
+        verify(bucketedExecutor, never()).submit(any());
+    }
+
     @Test
     public void testValidate() {
         Settings settings = mock(Settings.class);
@@ -239,6 +246,13 @@ public class MirrorRepositoryHookTest {
         return context;
     }
 
+    private RepositoryHookRequest buildRequest(RepositoryHookTrigger trigger, Repository repo) {
+        RepositoryHookRequest request = mock(RepositoryHookRequest.class);
+        when(request.getTrigger()).thenReturn(trigger);
+        when(request.getRepository()).thenReturn(repo);
+        return request;
+    }
+
     private Settings defaultSettings() {
         Map<String, Object> map = new HashMap<>();
         map.put(MirrorRepositoryHook.SETTING_MIRROR_REPO_URL, "");