diff --git a/google-cloud-core/src/main/java/com/google/cloud/ServiceOptions.java b/google-cloud-core/src/main/java/com/google/cloud/ServiceOptions.java
index 792609f4b4..2a84403af0 100644
--- a/google-cloud-core/src/main/java/com/google/cloud/ServiceOptions.java
+++ b/google-cloud-core/src/main/java/com/google/cloud/ServiceOptions.java
@@ -218,7 +218,7 @@ public B setCredentials(Credentials credentials) {
       }
 
       if (this.quotaProjectId == null && credentials instanceof QuotaProjectIdProvider) {
-        this.quotaProjectId = ((ServiceAccountCredentials) credentials).getQuotaProjectId();
+        this.quotaProjectId = ((QuotaProjectIdProvider) credentials).getQuotaProjectId();
       }
       return self();
     }