diff --git a/src/services/management/__tests__/management-auth.test.ts b/src/services/management/__tests__/management-auth.test.ts
new file mode 100644
index 0000000..f5b5282
--- /dev/null
+++ b/src/services/management/__tests__/management-auth.test.ts
@@ -0,0 +1,53 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+const cookieSet = vi.hoisted(() => vi.fn());
+
+vi.mock("next/headers", () => ({
+  cookies: vi.fn(async () => ({ set: cookieSet })),
+}));
+
+import { createManagerSession } from "../management-auth";
+
+describe("Manager session cookie", () => {
+  const originalAppUrl = process.env.NEXT_PUBLIC_APP_URL;
+  const originalAdminEmail = process.env.MANAGER_ADMIN_EMAIL;
+  const originalAuthSecret = process.env.MANAGER_AUTH_SECRET;
+
+  afterEach(() => {
+    if (originalAppUrl === undefined) delete process.env.NEXT_PUBLIC_APP_URL;
+    else process.env.NEXT_PUBLIC_APP_URL = originalAppUrl;
+    if (originalAdminEmail === undefined) delete process.env.MANAGER_ADMIN_EMAIL;
+    else process.env.MANAGER_ADMIN_EMAIL = originalAdminEmail;
+    if (originalAuthSecret === undefined) delete process.env.MANAGER_AUTH_SECRET;
+    else process.env.MANAGER_AUTH_SECRET = originalAuthSecret;
+    cookieSet.mockReset();
+  });
+
+  it("does not mark the cookie Secure for an HTTP deployment", async () => {
+    process.env.NEXT_PUBLIC_APP_URL = "http://manager.example.com";
+    process.env.MANAGER_ADMIN_EMAIL = "admin@example.com";
+    process.env.MANAGER_AUTH_SECRET = "test-secret";
+
+    await createManagerSession();
+
+    expect(cookieSet).toHaveBeenCalledWith(
+      "nextchair_manager_session",
+      expect.any(String),
+      expect.objectContaining({ secure: false, path: "/" }),
+    );
+  });
+
+  it("marks the cookie Secure for an HTTPS deployment", async () => {
+    process.env.NEXT_PUBLIC_APP_URL = "https://manager.example.com";
+    process.env.MANAGER_ADMIN_EMAIL = "admin@example.com";
+    process.env.MANAGER_AUTH_SECRET = "test-secret";
+
+    await createManagerSession();
+
+    expect(cookieSet).toHaveBeenCalledWith(
+      "nextchair_manager_session",
+      expect.any(String),
+      expect.objectContaining({ secure: true, path: "/" }),
+    );
+  });
+});
diff --git a/src/services/management/management-auth.ts b/src/services/management/management-auth.ts
index fada80a..c3960e7 100644
--- a/src/services/management/management-auth.ts
+++ b/src/services/management/management-auth.ts
@@ -1,5 +1,6 @@
 import { createHmac, timingSafeEqual } from "node:crypto";
 import { cookies } from "next/headers";
+import { isSecureDeployment } from "@/lib/security/cookie-security";
 import { getManagerConfig } from "./manager-config";
 
 const COOKIE_NAME = "nextchair_manager_session";
@@ -27,8 +28,10 @@ export async function createManagerSession() {
   (await cookies()).set(COOKIE_NAME, `${value}.${signature(value, config.authSecret)}`, {
     httpOnly: true,
     sameSite: "strict",
-    secure: process.env.NODE_ENV === "production",
-    path: "/manager",
+    secure: isSecureDeployment(),
+    // The Manager UI is under /manager, but its authenticated API is under
+    // /api/manager, so the cookie must cover both paths.
+    path: "/",
     maxAge: 60 * 60 * 8,
   });
 }