diff --git a/src/auth/jwtclient.ts b/src/auth/jwtclient.ts
index 31c41dbd..a2d753d2 100644
--- a/src/auth/jwtclient.ts
+++ b/src/auth/jwtclient.ts
@@ -163,12 +163,17 @@ export class JWT extends OAuth2Client implements IdTokenProvider {
           scopes = this.defaultScopes;
         }
 
+        const useScopes =
+          this.useJWTAccessWithScope ||
+          this.universeDomain !== DEFAULT_UNIVERSE;
+
         const headers = await this.access.getRequestHeaders(
           url ?? undefined,
           this.additionalClaims,
           // Scopes take precedent over audience for signing,
-          // so we only provide them if useJWTAccessWithScope is on
-          this.useJWTAccessWithScope ? scopes : undefined
+          // so we only provide them if `useJWTAccessWithScope` is on or
+          // if we are in a non-default universe
+          useScopes ? scopes : undefined
         );
 
         return {headers: this.addSharedMetadataHeaders(headers)};
diff --git a/test/test.jwt.ts b/test/test.jwt.ts
index fc11bd02..79eb1605 100644
--- a/test/test.jwt.ts
+++ b/test/test.jwt.ts
@@ -896,7 +896,7 @@ describe('jwt', () => {
       );
     });
 
-    it('signs JWT with audience if: user scope = true, default scope = false, audience = falsy, useJWTAccessWithScope = true', async () => {
+    it('signs JWT with scopes if: user scope = true, default scope = false, audience = falsy, useJWTAccessWithScope = true', async () => {
       const stubGetRequestHeaders = sandbox.stub().returns({});
       const stubJWTAccess = sandbox.stub(jwtaccess, 'JWTAccess').returns({
         getRequestHeaders: stubGetRequestHeaders,
@@ -918,7 +918,7 @@ describe('jwt', () => {
       );
     });
 
-    it('signs JWT with audience if: user scope = false, default scope = true, audience = falsy, useJWTAccessWithScope = true', async () => {
+    it('signs JWT with scopes if: user scope = false, default scope = true, audience = falsy, useJWTAccessWithScope = true', async () => {
       const stubGetRequestHeaders = sandbox.stub().returns({});
       const stubJWTAccess = sandbox.stub(jwtaccess, 'JWTAccess').returns({
         getRequestHeaders: stubGetRequestHeaders,
@@ -939,7 +939,7 @@ describe('jwt', () => {
       ]);
     });
 
-    it('signs JWT with audience if: user scope = true, default scope = true, audience = falsy, useJWTAccessWithScope = true', async () => {
+    it('signs JWT with scopes if: user scope = true, default scope = true, audience = falsy, useJWTAccessWithScope = true', async () => {
       const stubGetRequestHeaders = sandbox.stub().returns({});
       const stubJWTAccess = sandbox.stub(jwtaccess, 'JWTAccess').returns({
         getRequestHeaders: stubGetRequestHeaders,
@@ -962,7 +962,7 @@ describe('jwt', () => {
       );
     });
 
-    it('signs JWT with audience if: user scope = true, default scope = false, audience = truthy, useJWTAccessWithScope = true', async () => {
+    it('signs JWT with scopes if: user scope = true, default scope = false, audience = truthy, useJWTAccessWithScope = true', async () => {
       const stubGetRequestHeaders = sandbox.stub().returns({});
       const stubJWTAccess = sandbox.stub(jwtaccess, 'JWTAccess').returns({
         getRequestHeaders: stubGetRequestHeaders,
@@ -984,7 +984,7 @@ describe('jwt', () => {
       );
     });
 
-    it('signs JWT with audience if: user scope = true, default scope = true, audience = truthy, useJWTAccessWithScope = true', async () => {
+    it('signs JWT with scopes if: user scope = true, default scope = true, audience = truthy, useJWTAccessWithScope = true', async () => {
       const stubGetRequestHeaders = sandbox.stub().returns({});
       const stubJWTAccess = sandbox.stub(jwtaccess, 'JWTAccess').returns({
         getRequestHeaders: stubGetRequestHeaders,
@@ -1007,7 +1007,7 @@ describe('jwt', () => {
       );
     });
 
-    it('signs JWT with audience if: user scope = true, default scope = true, audience = truthy, universeDomain = not default universe', async () => {
+    it('signs JWT with scopes if: user scope = true, default scope = true, audience = truthy, universeDomain = not default universe', async () => {
       const stubGetRequestHeaders = sandbox.stub().returns({});
       const stubJWTAccess = sandbox.stub(jwtaccess, 'JWTAccess').returns({
         getRequestHeaders: stubGetRequestHeaders,
@@ -1025,11 +1025,11 @@ describe('jwt', () => {
         stubGetRequestHeaders,
         'https//beepboop.googleapis.com',
         undefined,
-        undefined
+        ['scope1', 'scope2']
       );
     });
 
-    it('signs JWT with audience if: user scope = true, default scope = true, audience = truthy, useJWTAccessWithScope = true, universeDomain = not default universe', async () => {
+    it('signs JWT with scopes if: user scope = true, default scope = true, audience = truthy, useJWTAccessWithScope = true, universeDomain = not default universe', async () => {
       const stubGetRequestHeaders = sandbox.stub().returns({});
       const stubJWTAccess = sandbox.stub(jwtaccess, 'JWTAccess').returns({
         getRequestHeaders: stubGetRequestHeaders,