diff --git a/src/github/credentials.ts b/src/github/credentials.ts
index 9abe709905..056220da2d 100644
--- a/src/github/credentials.ts
+++ b/src/github/credentials.ts
@@ -53,8 +53,20 @@ export async function findExistingSession(
 	authProviderId: AuthProvider,
 	getSession: AuthenticationSessionGetter = (providerId, scopes, options) => vscode.authentication.getSession(providerId, scopes, options),
 ): Promise<ExistingSession | undefined> {
-	// Establish the preferred account with the normal scopes before looking for broader sessions.
-	// Otherwise, a single broader session from another account can override the workspace preference.
+	// Establish the preferred account across all scopes before looking for its best session.
+	// A scope-specific lookup can otherwise fall back to the only account with those scopes.
+	const preferredSession = await getSession(authProviderId, [], { silent: true });
+	if (preferredSession) {
+		const scopesInPreferenceOrder = [SCOPES_WITH_ADDITIONAL, SCOPES_OLD, SCOPES_OLDEST];
+		for (const scopes of scopesInPreferenceOrder) {
+			const session = await getSession(authProviderId, scopes, { silent: true, account: preferredSession.account });
+			if (session) {
+				return { session, scopes };
+			}
+		}
+		return { session: preferredSession, scopes: [...preferredSession.scopes] };
+	}
+
 	const scopePreferences = [
 		{ scopes: SCOPES_OLD, broaderScopes: [SCOPES_WITH_ADDITIONAL] },
 		{ scopes: SCOPES_OLDEST, broaderScopes: [SCOPES_WITH_ADDITIONAL, SCOPES_OLD] },
diff --git a/src/test/github/credentials.test.ts b/src/test/github/credentials.test.ts
index e6163eac31..967c589bb0 100644
--- a/src/test/github/credentials.test.ts
+++ b/src/test/github/credentials.test.ts
@@ -52,13 +52,16 @@ describe('CredentialStore', function () {
 
 			const result = await findExistingSession(AuthProvider.github, async (_providerId, scopes, options) => {
 				requests.push({ scopes, accountId: options.account?.id });
-				if (options.account?.id === 'second') {
-					return undefined;
+				if (!scopes.length) {
+					return secondAccountDefault;
+				}
+				if (options.account?.id === 'second' && scopesEqual(scopes, defaultScopes)) {
+					return secondAccountDefault;
 				}
 				if (scopesEqual(scopes, defaultScopes)) {
 					return secondAccountDefault;
 				}
-				if (scopesEqual(scopes, additionalScopes)) {
+				if (!options.account && scopesEqual(scopes, additionalScopes)) {
 					return firstAccountAdditional;
 				}
 				return undefined;
@@ -67,7 +70,35 @@ describe('CredentialStore', function () {
 			strictEqual(result?.session, secondAccountDefault);
 			deepStrictEqual(result?.scopes, defaultScopes);
 			deepStrictEqual(requests, [
-				{ scopes: defaultScopes, accountId: undefined },
+				{ scopes: [], accountId: undefined },
+				{ scopes: additionalScopes, accountId: 'second' },
+				{ scopes: defaultScopes, accountId: 'second' },
+			]);
+		});
+
+		it('uses the preferred account when accounts have different scope sets', async function () {
+			const firstAccountDefault = createSession('first-default', 'first', defaultScopes);
+			const secondAccountAdditional = createSession('second-additional', 'second', additionalScopes);
+			const requests: { scopes: readonly string[], accountId?: string }[] = [];
+
+			const result = await findExistingSession(AuthProvider.github, async (_providerId, scopes, options) => {
+				requests.push({ scopes, accountId: options.account?.id });
+				if (!scopes.length) {
+					return secondAccountAdditional;
+				}
+				if (!options.account && scopesEqual(scopes, defaultScopes)) {
+					return firstAccountDefault;
+				}
+				if (options.account?.id === 'second' && scopesEqual(scopes, additionalScopes)) {
+					return secondAccountAdditional;
+				}
+				return undefined;
+			});
+
+			strictEqual(result?.session, secondAccountAdditional);
+			deepStrictEqual(result?.scopes, additionalScopes);
+			deepStrictEqual(requests, [
+				{ scopes: [], accountId: undefined },
 				{ scopes: additionalScopes, accountId: 'second' },
 			]);
 		});
@@ -77,6 +108,9 @@ describe('CredentialStore', function () {
 			const preferredAdditional = createSession('preferred-additional', 'preferred', additionalScopes);
 
 			const result = await findExistingSession(AuthProvider.github, async (_providerId, scopes, options) => {
+				if (!scopes.length) {
+					return preferredDefault;
+				}
 				if (options.account?.id === 'preferred' && scopesEqual(scopes, additionalScopes)) {
 					return preferredAdditional;
 				}
@@ -104,7 +138,7 @@ describe('CredentialStore', function () {
 
 			const additionalSession = createSession('additional', 'additional', additionalScopes);
 			const additionalResult = await findExistingSession(AuthProvider.github, async (_providerId, scopes, options) => {
-				if (!options.account && scopesEqual(scopes, additionalScopes)) {
+				if (!scopes.length || (options.account?.id === 'additional' && scopesEqual(scopes, additionalScopes))) {
 					return additionalSession;
 				}
 				return undefined;