diff --git a/app/routes/auth/oidc-callback.ts b/app/routes/auth/oidc-callback.ts
index 01b494f..15b79ce 100644
--- a/app/routes/auth/oidc-callback.ts
+++ b/app/routes/auth/oidc-callback.ts
@@ -74,6 +74,7 @@ export async function loader({ request, context, url }: Route.LoaderArgs) {
     },
     {
       initialRole: claimedRole ?? config.oidc?.default_role,
+      syncRole: claimedRole,
     },
   );
 
diff --git a/app/server/web/auth.ts b/app/server/web/auth.ts
index fa48565..910675b 100644
--- a/app/server/web/auth.ts
+++ b/app/server/web/auth.ts
@@ -89,7 +89,7 @@ export interface AuthService {
   findOrCreateUser(
     subject: string,
     profile?: { name?: string; email?: string; picture?: string },
-    options?: { initialRole?: string },
+    options?: { initialRole?: string; syncRole?: string },
   ): Promise<string>;
 
   linkHeadscaleUser(userId: string, headscaleUserId: string): Promise<boolean>;
@@ -583,17 +583,21 @@ export function createAuthService(opts: AuthServiceOptions): AuthService {
   async function findOrCreateUser(
     subject: string,
     profile?: { name?: string; email?: string; picture?: string },
-    options?: { initialRole?: string },
+    options?: { initialRole?: string; syncRole?: string },
   ): Promise<string> {
     const [existing] = await opts.db.select().from(users).where(eq(users.sub, subject)).limit(1);
 
     if (existing) {
+      const syncedRole = normalizeInitialRole(options?.syncRole);
       await opts.db
         .update(users)
         .set({
           name: profile?.name,
           email: profile?.email,
           picture: profile?.picture,
+          ...(syncedRole && existing.role !== "owner"
+            ? { role: syncedRole, caps: capsForRole(syncedRole) }
+            : {}),
           last_login_at: new Date(),
           updated_at: new Date(),
         })
diff --git a/config.example.yaml b/config.example.yaml
index da40854..7f90821 100644
--- a/config.example.yaml
+++ b/config.example.yaml
@@ -288,10 +288,11 @@ integration:
 #   # auditor, viewer, member. The owner role is only granted to the first user.
 #   default_role: "member"
 #
-#   # Optional OIDC claim to read a Headplane role from when creating a new user.
+#   # Optional OIDC claim to read a Headplane role from when creating or syncing a user.
 #   # This can be a string claim, or an array claim containing one of the valid
 #   # roles above. If present and valid, it takes precedence over default_role.
-#   # Configure your IdP to map groups or client roles into this claim.
+#   # Configure your IdP to map groups or client roles into this claim. Existing
+#   # non-owner users are updated on their next OIDC sign-in when this claim changes.
 #   role_claim: "headplane_role"
 #
 #   # Allow ID token verification with legacy RSA keys smaller than 2048 bits.
diff --git a/docs/features/sso.md b/docs/features/sso.md
index 374039a..bc58723 100644
--- a/docs/features/sso.md
+++ b/docs/features/sso.md
@@ -257,10 +257,12 @@ valid roles. This lets providers such as Keycloak map groups or client roles to
 a final Headplane role before login. When both `role_claim` and `default_role`
 are configured, a valid role claim takes precedence for new users.
 
-Automatic role assignment only applies when Headplane creates a user for the
-first time. It does not overwrite roles that were already assigned in Headplane.
-The **Owner** role is reserved for the first-login bootstrap and cannot be
-granted by `default_role` or `role_claim`.
+For users that already exist in Headplane, a valid `role_claim` is synced on
+each OIDC login. If their IdP groups or client roles start matching a different
+Headplane role, their Headplane permissions are updated at their next sign-in.
+`default_role` remains a creation-time fallback only and does not overwrite
+existing roles. The **Owner** role is reserved for the first-login bootstrap and
+cannot be granted or overwritten by `default_role` or `role_claim`.
 
 ### API Key Sessions
 
diff --git a/tests/unit/auth/auth-service.test.ts b/tests/unit/auth/auth-service.test.ts
index 27240b7..b32cd88 100644
--- a/tests/unit/auth/auth-service.test.ts
+++ b/tests/unit/auth/auth-service.test.ts
@@ -65,6 +65,35 @@ describe("findOrCreateUser", () => {
     expect(user?.name).toBe("New");
     expect(user?.email).toBe("new@test.com");
   });
+
+  test("syncs an existing non-owner role when explicitly provided", async () => {
+    await auth.findOrCreateUser("sub-owner");
+    await auth.findOrCreateUser("sub-1", { name: "User" });
+
+    await auth.findOrCreateUser("sub-1", { name: "User" }, { syncRole: "admin" });
+
+    const role = await auth.roleForSubject("sub-1");
+    expect(role).toBe("admin");
+  });
+
+  test("does not apply initial role to an existing user", async () => {
+    await auth.findOrCreateUser("sub-owner");
+    await auth.findOrCreateUser("sub-1", { name: "User" });
+
+    await auth.findOrCreateUser("sub-1", { name: "User" }, { initialRole: "admin" });
+
+    const role = await auth.roleForSubject("sub-1");
+    expect(role).toBe("member");
+  });
+
+  test("does not sync the owner role", async () => {
+    await auth.findOrCreateUser("sub-owner");
+
+    await auth.findOrCreateUser("sub-owner", { name: "Owner" }, { syncRole: "admin" });
+
+    const role = await auth.roleForSubject("sub-owner");
+    expect(role).toBe("owner");
+  });
 });
 
 describe("linkHeadscaleUser", () => {