diff --git a/src/main/java/com/segment/analytics/android/integrations/firebase/FirebaseIntegration.java b/src/main/java/com/segment/analytics/android/integrations/firebase/FirebaseIntegration.java
index 1b4f042..c2dfb67 100644
--- a/src/main/java/com/segment/analytics/android/integrations/firebase/FirebaseIntegration.java
+++ b/src/main/java/com/segment/analytics/android/integrations/firebase/FirebaseIntegration.java
@@ -214,7 +214,7 @@ && isNullOrEmpty(properties.currency())) {
   }
 
   public static String makeKey(String key) {
-    String[] forbiddenChars = {".", "-", " "};
+    String[] forbiddenChars = {".", "-", " ", ":"};
     for (String forbidden : forbiddenChars) {
       if (key.contains(forbidden)) {
         key = key.trim().replace(forbidden, "_");
diff --git a/src/test/java/com/segment/analytics/android/integration/firebase/FirebaseTest.java b/src/test/java/com/segment/analytics/android/integration/firebase/FirebaseTest.java
index 04c9a93..429fcf9 100644
--- a/src/test/java/com/segment/analytics/android/integration/firebase/FirebaseTest.java
+++ b/src/test/java/com/segment/analytics/android/integration/firebase/FirebaseTest.java
@@ -205,6 +205,12 @@ public void makeKeyWithDashAndDot() {
         verify(firebase).logEvent(eq("test_event_dashed_and_dotted"), bundleEq(new Bundle()));
     }
 
+    @Test
+    public void makeKeyWithColon() {
+        integration.track(new TrackPayload.Builder().anonymousId("12345").event("test:colon").build());
+        verify(firebase).logEvent(eq("test_colon"), bundleEq(new Bundle()));
+    }
+
     /**
      * Uses the string representation of the object. Useful for JSON objects.
      * @param expected Expected object