diff --git a/packages/better-auth/src/db/internal-adapter.test.ts b/packages/better-auth/src/db/internal-adapter.test.ts
index 5f216d443b..9d5ffd2051 100644
--- a/packages/better-auth/src/db/internal-adapter.test.ts
+++ b/packages/better-auth/src/db/internal-adapter.test.ts
@@ -635,4 +635,120 @@ describe("internal adapter test", async () => {
 		accounts = await internalAdapter.findAccounts(user.id);
 		expect(accounts.length).toBe(0);
 	});
+
+	it("should update session and active-sessions list in secondary storage", async () => {
+		const testMap = new Map<string, string>();
+		const testExpirationMap = new Map<string, number>();
+
+		const testDb = new Database(":memory:");
+		const testSqliteDialect = new SqliteDialect({
+			database: testDb,
+		});
+
+		const testOpts = {
+			database: {
+				dialect: testSqliteDialect,
+				type: "sqlite",
+			},
+			secondaryStorage: {
+				set(key: string, value: string, ttl?: number) {
+					testMap.set(key, value);
+					if (ttl !== undefined) {
+						testExpirationMap.set(key, ttl);
+					}
+				},
+				get(key: string) {
+					return testMap.get(key) || null;
+				},
+				delete(key: string) {
+					testMap.delete(key);
+					testExpirationMap.delete(key);
+				},
+			},
+		} satisfies BetterAuthOptions;
+
+		// Run migrations for the new database
+		(await getMigrations(testOpts)).runMigrations();
+
+		const testCtx = await init(testOpts);
+		const testInternalAdapter = testCtx.internalAdapter;
+
+		// Create a user first
+		const user = await testInternalAdapter.createUser({
+			name: "test-user-update",
+			email: "test-update@email.com",
+		});
+
+		// Create a session
+		const session = await testInternalAdapter.createSession(user.id);
+
+		// Verify session is in secondary storage
+		const storedSessionStr = testMap.get(session.token);
+		expect(storedSessionStr).toBeDefined();
+
+		const storedSession = safeJSONParse<{
+			session: Session;
+			user: User;
+		}>(storedSessionStr!);
+
+		expect(storedSession?.session.ipAddress).toBe("");
+
+		// Get initial active-sessions list
+		const initialListStr = testMap.get(`active-sessions-${user.id}`);
+		expect(initialListStr).toBeDefined();
+		const initialList = safeJSONParse<{ token: string; expiresAt: number }[]>(
+			initialListStr!,
+		);
+		expect(initialList).toBeDefined();
+		expect(initialList!.length).toBe(1);
+		const initialExpiresAt = initialList![0]!.expiresAt;
+
+		// Update the session with new ipAddress and expiresAt
+		const updatedIpAddress = "192.168.1.1";
+		const newExpiresAt = new Date(initialExpiresAt + 60 * 60 * 1000);
+		await testInternalAdapter.updateSession(session.token, {
+			ipAddress: updatedIpAddress,
+			expiresAt: newExpiresAt,
+		});
+
+		// Get the session from secondary storage again
+		const updatedStoredSessionStr = testMap.get(session.token);
+		expect(updatedStoredSessionStr).toBeDefined();
+
+		const updatedStoredSession = safeJSONParse<{
+			session: Session;
+			user: User;
+		}>(updatedStoredSessionStr!);
+
+		// The session in secondary storage MUST have the updated data
+		expect(updatedStoredSession?.session.ipAddress).toBe(updatedIpAddress);
+
+		// User should still be intact
+		expect(updatedStoredSession?.user.id).toBe(user.id);
+
+		// Get updated active-sessions list
+		const updatedListStr = testMap.get(`active-sessions-${user.id}`);
+		expect(updatedListStr).toBeDefined();
+		const updatedList = safeJSONParse<{ token: string; expiresAt: number }[]>(
+			updatedListStr!,
+		);
+		expect(updatedList).toBeDefined();
+
+		// The expiresAt in active-sessions list should be updated
+		expect(updatedList!.length).toBe(1);
+		expect(updatedList![0]!.token).toBe(session.token);
+		expect(updatedList![0]!.expiresAt).toBe(newExpiresAt.getTime());
+
+		// TTL should also be updated
+		const updatedTTL = testExpirationMap.get(`active-sessions-${user.id}`);
+		const expectedTTL = Math.floor(
+			(newExpiresAt.getTime() - Date.now()) / 1000,
+		);
+		expect(updatedTTL).toBeDefined();
+		expect(updatedTTL! - expectedTTL).toBeLessThanOrEqual(1);
+		expect(updatedTTL! - expectedTTL).toBeGreaterThanOrEqual(0);
+
+		// Clean up DB
+		testDb.close();
+	});
 });
diff --git a/packages/better-auth/src/db/internal-adapter.ts b/packages/better-auth/src/db/internal-adapter.ts
index 4e2a34444e..5295fe5825 100644
--- a/packages/better-auth/src/db/internal-adapter.ts
+++ b/packages/better-auth/src/db/internal-adapter.ts
@@ -507,21 +507,79 @@ export const createInternalAdapter = (
 					? {
 							async fn(data) {
 								const currentSession = await secondaryStorage.get(sessionToken);
-								let updatedSession: Session | null = null;
-								if (currentSession) {
-									const parsedSession = safeJSONParse<{
-										session: Session;
-										user: User;
-									}>(currentSession);
-									if (!parsedSession) return null;
-									updatedSession = {
-										...parsedSession.session,
-										...data,
-									};
-									return updatedSession;
-								} else {
+								if (!currentSession) {
 									return null;
 								}
+
+								const parsedSession = safeJSONParse<{
+									session: Session;
+									user: User;
+								}>(currentSession);
+								if (!parsedSession) return null;
+
+								const mergedSession = {
+									...parsedSession.session,
+									...data,
+									expiresAt: new Date(
+										data.expiresAt ?? parsedSession.session.expiresAt,
+									),
+									createdAt: new Date(parsedSession.session.createdAt),
+									updatedAt: new Date(
+										data.updatedAt ?? parsedSession.session.updatedAt,
+									),
+								};
+
+								const updatedSession = parseSessionOutput(
+									ctx.options,
+									mergedSession,
+								);
+
+								const now = Date.now();
+								const expiresMs = new Date(updatedSession.expiresAt).getTime();
+								const sessionTTL = Math.max(
+									Math.floor((expiresMs - now) / 1000),
+									0,
+								);
+
+								if (sessionTTL > 0) {
+									await secondaryStorage.set(
+										sessionToken,
+										JSON.stringify({
+											session: updatedSession,
+											user: parsedSession.user,
+										}),
+										sessionTTL,
+									);
+
+									const listKey = `active-sessions-${updatedSession.userId}`;
+									const listRaw = await secondaryStorage.get(listKey);
+									const list: { token: string; expiresAt: number }[] = listRaw
+										? safeJSONParse(listRaw) || []
+										: [];
+
+									const filtered = list
+										.filter(
+											(s) => s.token !== sessionToken && s.expiresAt > now,
+										)
+										.concat([{ token: sessionToken, expiresAt: expiresMs }]);
+
+									const sorted = filtered.sort(
+										(a, b) => a.expiresAt - b.expiresAt,
+									);
+									const furthestSessionExp = sorted.at(-1)?.expiresAt;
+
+									if (furthestSessionExp && furthestSessionExp > now) {
+										await secondaryStorage.set(
+											listKey,
+											JSON.stringify(sorted),
+											Math.floor((furthestSessionExp - now) / 1000),
+										);
+									} else {
+										await secondaryStorage.delete(listKey);
+									}
+								}
+
+								return updatedSession;
 							},
 							executeMainFn: options.session?.storeSessionInDatabase,
 						}