diff --git a/CHANGELOG.md b/CHANGELOG.md
index e69de29bb2d..a2b36e6c3f2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -0,0 +1 @@
+- Fix python function discovery where credentials are needed (#6274).
diff --git a/src/deploy/functions/prepare.ts b/src/deploy/functions/prepare.ts
index b43e79f4da8..b08c0286a6b 100644
--- a/src/deploy/functions/prepare.ts
+++ b/src/deploy/functions/prepare.ts
@@ -98,7 +98,8 @@ export async function prepare(
   const wantBackends: Record<string, backend.Backend> = {};
   for (const [codebase, wantBuild] of Object.entries(wantBuilds)) {
     const config = configForCodebase(context.config, codebase);
-    const firebaseEnvs = functionsEnv.loadFirebaseEnvs(firebaseConfig, projectId);
+    const firebaseEnvs = await functionsEnv.loadFirebaseEnvs(firebaseConfig, projectId);
+
     const userEnvOpt: functionsEnv.UserEnvsOpts = {
       functionsSource: options.config.path(config.source),
       projectId: projectId,
@@ -448,7 +449,7 @@ export async function loadCodebases(
     logger.debug(`Building ${runtimeDelegate.name} source`);
     await runtimeDelegate.build();
 
-    const firebaseEnvs = functionsEnv.loadFirebaseEnvs(firebaseConfig, projectId);
+    const firebaseEnvs = await functionsEnv.loadFirebaseEnvs(firebaseConfig, projectId);
     logLabeledBullet(
       "functions",
       `Loading and analyzing source code for codebase ${codebase} to determine what to deploy`
diff --git a/src/functions/env.ts b/src/functions/env.ts
index b640aff443e..b439f19f13d 100644
--- a/src/functions/env.ts
+++ b/src/functions/env.ts
@@ -5,6 +5,8 @@ import * as path from "path";
 import { FirebaseError } from "../error";
 import { logger } from "../logger";
 import { logBullet, logWarning } from "../utils";
+import { getProjectDefaultAccount } from "../auth";
+import { getCredentialPathAsync } from "../defaultCredentials";
 
 const FUNCTIONS_EMULATOR_DOTENV = ".env.local";
 
@@ -403,12 +405,18 @@ export function loadUserEnvs({
  *
  * @return Environment varibles for functions.
  */
-export function loadFirebaseEnvs(
+export async function loadFirebaseEnvs(
   firebaseConfig: Record<string, any>,
   projectId: string
-): Record<string, string> {
+): Promise<Record<string, string>> {
+  let defaultCredPath = "";
+  const account = getProjectDefaultAccount();
+  if (account !== undefined) {
+    defaultCredPath = (await getCredentialPathAsync(account)) || "";
+  }
   return {
     FIREBASE_CONFIG: JSON.stringify(firebaseConfig),
     GCLOUD_PROJECT: projectId,
+    GOOGLE_APPLICATION_CREDENTIALS: defaultCredPath,
   };
 }