diff --git a/backend/src/services/app-connection/gcp/gcp-connection-fns.ts b/backend/src/services/app-connection/gcp/gcp-connection-fns.ts
index 39e56e055..dadfc7d43 100644
--- a/backend/src/services/app-connection/gcp/gcp-connection-fns.ts
+++ b/backend/src/services/app-connection/gcp/gcp-connection-fns.ts
@@ -146,6 +146,18 @@ export const getGcpSecretManagerProjects = async (appConnection: TGcpConnection)
 };
 
 export const validateGcpConnectionCredentials = async (appConnection: TGcpConnectionConfig) => {
+  // Check if provided service account email prefix matches organization ID.
+  // We do this to mitigate confused deputy attacks in multi-tenant instances
+  const expectedEmailPrefix = appConnection.orgId.split("-").slice(0, 2).join("-");
+  if (
+    appConnection.credentials.serviceAccountEmail &&
+    !appConnection.credentials.serviceAccountEmail.startsWith(expectedEmailPrefix)
+  ) {
+    throw new BadRequestError({
+      message: `GCP service account email must have a prefix of "${expectedEmailPrefix}"`
+    });
+  }
+
   await getAuthToken(appConnection);
 
   return appConnection.credentials;
diff --git a/backend/src/services/app-connection/gcp/gcp-connection-schemas.ts b/backend/src/services/app-connection/gcp/gcp-connection-schemas.ts
index 5ad919adc..3c313f205 100644
--- a/backend/src/services/app-connection/gcp/gcp-connection-schemas.ts
+++ b/backend/src/services/app-connection/gcp/gcp-connection-schemas.ts
@@ -11,7 +11,7 @@ import {
 import { GcpConnectionMethod } from "./gcp-connection-enums";
 
 export const GcpConnectionServiceAccountImpersonationCredentialsSchema = z.object({
-  serviceAccountEmail: z.string().trim().min(1, "Service account email required")
+  serviceAccountEmail: z.string().email().trim().min(1, "Service account email required")
 });
 
 const BaseGcpConnectionSchema = BaseAppConnectionSchema.extend({ app: z.literal(AppConnection.GCP) });
diff --git a/frontend/src/pages/organization/SettingsPage/components/AppConnectionsTab/components/AppConnectionForm/GcpConnectionForm.tsx b/frontend/src/pages/organization/SettingsPage/components/AppConnectionsTab/components/AppConnectionForm/GcpConnectionForm.tsx
index d647c29a6..bdcb96242 100644
--- a/frontend/src/pages/organization/SettingsPage/components/AppConnectionsTab/components/AppConnectionForm/GcpConnectionForm.tsx
+++ b/frontend/src/pages/organization/SettingsPage/components/AppConnectionsTab/components/AppConnectionForm/GcpConnectionForm.tsx
@@ -10,6 +10,7 @@ import {
   Select,
   SelectItem
 } from "@app/components/v2";
+import { useOrganization } from "@app/context";
 import { APP_CONNECTION_MAP, getAppConnectionMethodDetails } from "@app/helpers/appConnections";
 import { GcpConnectionMethod, TGcpConnection } from "@app/hooks/api/appConnections";
 import { AppConnection } from "@app/hooks/api/appConnections/enums";
@@ -32,7 +33,7 @@ const formSchema = z.discriminatedUnion("method", [
   rootSchema.extend({
     method: z.literal(GcpConnectionMethod.ServiceAccountImpersonation),
     credentials: z.object({
-      serviceAccountEmail: z.string().trim().min(1, "Service account email required")
+      serviceAccountEmail: z.string().email().trim().min(1, "Service account email required")
     })
   })
 ]);
@@ -49,6 +50,7 @@ export const GcpConnectionForm = ({ appConnection, onSubmit }: Props) => {
       method: GcpConnectionMethod.ServiceAccountImpersonation
     }
   });
+  const { currentOrg } = useOrganization();
 
   const {
     handleSubmit,
@@ -101,6 +103,7 @@ export const GcpConnectionForm = ({ appConnection, onSubmit }: Props) => {
               isError={Boolean(error?.message)}
               label="Service Account Email"
               className="group"
+              helperText={`Service account email must be prefixed with "${currentOrg.id.split("-").slice(0, 2).join("-")}".`}
             >
               <SecretInput
                 containerClassName="text-gray-400 group-focus-within:!border-primary-400/50 border border-mineshaft-500 bg-mineshaft-900 px-2.5 py-1.5"