diff --git a/.changeset/gentle-polar-claims.md b/.changeset/gentle-polar-claims.md
new file mode 100644
index 0000000000..18cfb89448
--- /dev/null
+++ b/.changeset/gentle-polar-claims.md
@@ -0,0 +1,5 @@
+---
+"@better-auth/core": minor
+---
+
+Identify Polar accounts by their userinfo subject and expose the scoped, nullable userinfo claims in `mapProfileToUser` instead of unrelated user profile fields.
diff --git a/packages/core/src/social-providers/polar.test.ts b/packages/core/src/social-providers/polar.test.ts
new file mode 100644
index 0000000000..0e4ad6f1f7
--- /dev/null
+++ b/packages/core/src/social-providers/polar.test.ts
@@ -0,0 +1,114 @@
+import { betterFetch } from "@better-fetch/fetch";
+import { beforeEach, describe, expect, expectTypeOf, it, vi } from "vitest";
+import type { PolarProfile } from "./polar";
+import { polar } from "./polar";
+
+vi.mock(import("@better-fetch/fetch"), () => ({
+	betterFetch: vi.fn(),
+}));
+
+const mockedBetterFetch = vi.mocked(betterFetch);
+const options = { clientId: "polar-client", clientSecret: "polar-secret" };
+
+/**
+ * @see https://github.com/polarsource/polar/blob/main/server/polar/oauth2/userinfo.py
+ * @see https://github.com/polarsource/polar/blob/main/server/polar/oauth2/schemas.py
+ */
+describe("Polar userinfo profiles", () => {
+	beforeEach(() => {
+		mockedBetterFetch.mockReset();
+	});
+
+	it("uses the userinfo subject for account identity", async () => {
+		const profile = {
+			sub: "polar-user",
+			email: "user@example.com",
+			email_verified: true,
+		} satisfies PolarProfile;
+		mockedBetterFetch.mockResolvedValueOnce({ data: profile, error: null });
+		const provider = polar(options);
+		const tokens = { accessToken: "polar-access-token" };
+		const result = await provider.getUserInfo(tokens);
+
+		expect(result?.user.email).toBe("user@example.com");
+		expect(result?.user.emailVerified).toBe(true);
+		expect(result?.data).toEqual(profile);
+		expect(provider.accountSubject({ tokens, profile })).toBe("polar-user");
+	});
+
+	it("maps an organization name without an email", async () => {
+		const profile = {
+			sub: "polar-organization",
+			name: "organization-slug",
+		} satisfies PolarProfile;
+		mockedBetterFetch.mockResolvedValueOnce({ data: profile, error: null });
+		const result = await polar(options).getUserInfo({ accessToken: "token" });
+
+		expect(result?.user.name).toBe("organization-slug");
+		expect(result?.user.email).toBeUndefined();
+		expect(result?.user.emailVerified).toBe(false);
+		expect(result?.data).toEqual(profile);
+	});
+
+	it("lets profile mapping supply an email for a subject-only response", async () => {
+		const profile = { sub: "polar-user" } satisfies PolarProfile;
+		mockedBetterFetch.mockResolvedValueOnce({ data: profile, error: null });
+		const mapProfileToUser = vi.fn((claims: PolarProfile) => ({
+			name: "Mapped User",
+			email: `${claims.sub}@example.com`,
+		}));
+		const result = await polar({ ...options, mapProfileToUser }).getUserInfo({
+			accessToken: "token",
+		});
+
+		expect(mapProfileToUser).toHaveBeenCalledWith(profile);
+		expect(result?.user).toMatchObject({
+			name: "Mapped User",
+			email: "polar-user@example.com",
+			emailVerified: false,
+		});
+		expect(result?.data).toEqual(profile);
+	});
+
+	it("preserves nullable claims and profile mapping overrides", async () => {
+		const profile = {
+			sub: "polar-user",
+			name: null,
+			email: null,
+			email_verified: null,
+		} satisfies PolarProfile;
+		mockedBetterFetch.mockResolvedValueOnce({ data: profile, error: null });
+		const mapProfileToUser = vi.fn(() => ({
+			name: "Mapped User",
+			email: "mapped@example.com",
+			image: "https://example.com/avatar.png",
+		}));
+		const result = await polar({ ...options, mapProfileToUser }).getUserInfo({
+			accessToken: "token",
+		});
+
+		expect(mapProfileToUser).toHaveBeenCalledWith(profile);
+		expect(result?.data).toEqual(profile);
+		expect(result?.user).toEqual({
+			name: "Mapped User",
+			email: "mapped@example.com",
+			image: "https://example.com/avatar.png",
+			emailVerified: false,
+		});
+	});
+
+	it("exposes nullable optional claims in profile mapping", () => {
+		polar({
+			...options,
+			mapProfileToUser(profile) {
+				expectTypeOf(profile.sub).toEqualTypeOf<string>();
+				expectTypeOf(profile.name).toEqualTypeOf<string | null | undefined>();
+				expectTypeOf(profile.email).toEqualTypeOf<string | null | undefined>();
+				expectTypeOf(profile.email_verified).toEqualTypeOf<
+					boolean | null | undefined
+				>();
+				return {};
+			},
+		});
+	});
+});
diff --git a/packages/core/src/social-providers/polar.ts b/packages/core/src/social-providers/polar.ts
index 0892057461..1ae9dcdfb6 100644
--- a/packages/core/src/social-providers/polar.ts
+++ b/packages/core/src/social-providers/polar.ts
@@ -6,28 +6,12 @@ import {
 	validateAuthorizationCode,
 } from "../oauth2";
 
+/** Claims returned by Polar's OAuth userinfo endpoint for a user or organization. */
 export interface PolarProfile {
-	id: string;
-	email: string;
-	username: string;
-	avatar_url: string;
-	github_username?: string | undefined;
-	account_id?: string | undefined;
-	public_name?: string | undefined;
-	email_verified?: boolean | undefined;
-	profile_settings?:
-		| {
-				profile_settings_enabled?: boolean;
-				profile_settings_public_name?: string;
-				profile_settings_public_avatar?: string;
-				profile_settings_public_bio?: string;
-				profile_settings_public_location?: string;
-				profile_settings_public_website?: string;
-				profile_settings_public_twitter?: string;
-				profile_settings_public_github?: string;
-				profile_settings_public_email?: string;
-		  }
-		| undefined;
+	sub: string;
+	name?: string | null | undefined;
+	email?: string | null | undefined;
+	email_verified?: boolean | null | undefined;
 }
 
 export interface PolarOptions extends ProviderOptions<PolarProfile> {}
@@ -37,7 +21,7 @@ export const polar = (options: PolarOptions) => {
 	return {
 		id: "polar",
 		name: "Polar",
-		accountSubject: ({ profile }) => profile.id,
+		accountSubject: ({ profile }) => profile.sub,
 		createAuthorizationURL({
 			state,
 			scopes,
@@ -104,9 +88,8 @@ export const polar = (options: PolarOptions) => {
 			// We check for it first, then default to false for security consistency.
 			return {
 				user: {
-					name: profile.public_name || profile.username || "",
+					name: profile.name ?? "",
 					email: profile.email,
-					image: profile.avatar_url,
 					emailVerified: profile.email_verified ?? false,
 					...userMap,
 				},