diff --git a/appjar/src/main/java/com/google/gerrit/server/GroupCache.java b/appjar/src/main/java/com/google/gerrit/server/GroupCache.java
index 44b814ced0..6afaabb119 100644
--- a/appjar/src/main/java/com/google/gerrit/server/GroupCache.java
+++ b/appjar/src/main/java/com/google/gerrit/server/GroupCache.java
@@ -193,4 +193,11 @@ public class GroupCache {
     }
     return m;
   }
+
+  /** Force the entire group cache to flush from memory and recompute. */
+  public void flush() {
+    synchronized (byAccount) {
+      byAccount.clear();
+    }
+  }
 }
diff --git a/appjar/src/main/java/com/google/gerrit/server/ssh/AdminFlushGroupCache.java b/appjar/src/main/java/com/google/gerrit/server/ssh/AdminFlushGroupCache.java
new file mode 100644
index 0000000000..6d8d112cd0
--- /dev/null
+++ b/appjar/src/main/java/com/google/gerrit/server/ssh/AdminFlushGroupCache.java
@@ -0,0 +1,30 @@
+// Copyright 2008 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.ssh;
+
+import com.google.gerrit.server.GroupCache;
+
+/** Causes the {@link GroupCache} to purge all entries and reload. */
+class AdminFlushGroupCache extends AbstractCommand {
+  @Override
+  protected void run(String[] args) throws Failure {
+    final GroupCache gc = getGerritServer().getGroupCache();
+    if (gc.isAdministrator(getAccountId())) {
+      gc.flush();
+    } else {
+      throw new Failure(1, "fatal: Not a Gerrit administrator");
+    }
+  }
+}
diff --git a/appjar/src/main/java/com/google/gerrit/server/ssh/GerritCommandFactory.java b/appjar/src/main/java/com/google/gerrit/server/ssh/GerritCommandFactory.java
index fbef552900..10d3d37d2d 100644
--- a/appjar/src/main/java/com/google/gerrit/server/ssh/GerritCommandFactory.java
+++ b/appjar/src/main/java/com/google/gerrit/server/ssh/GerritCommandFactory.java
@@ -55,6 +55,10 @@ class GerritCommandFactory implements CommandFactory {
       return new Receive();
     }
 
+    if ("gerrit-flush-group-cache".equals(cmd)) {
+      return new AdminFlushGroupCache();
+    }
+
     return new AbstractCommand() {
       @Override
       protected void run(final String[] argv) throws Failure {