diff --git a/crates/server/src/console/mod.rs b/crates/server/src/console/mod.rs
index 76cc752c7..3ff5fd6a4 100755
--- a/crates/server/src/console/mod.rs
+++ b/crates/server/src/console/mod.rs
@@ -55,6 +55,9 @@ pub struct ConsoleState {
     /// `/console/metrics-data` response with latency segments (same data the
     /// top-level `/metrics` handler adds).
     pub metrics: Arc<extenddb_core::metrics::MetricsCollector>,
+    /// Whether the session cookie carries `Secure`: true when the server
+    /// serves TLS, false in dev mode, which serves plain HTTP.
+    pub secure_cookies: bool,
 }
 
 /// Build the console router.
diff --git a/crates/server/src/console/pages/auth_pages.rs b/crates/server/src/console/pages/auth_pages.rs
index b869e5434..9919b67a8 100755
--- a/crates/server/src/console/pages/auth_pages.rs
+++ b/crates/server/src/console/pages/auth_pages.rs
@@ -71,9 +71,7 @@ pub async fn login_submit(
     };
 
     let (token, _csrf) = state.sessions.create(identity).await;
-    let cookie = format!(
-        "extenddb_session={token}; Path=/console; HttpOnly; SameSite=Strict; Max-Age=28800"
-    );
+    let cookie = session_cookie(&token, 28800, state.secure_cookies);
 
     (
         StatusCode::SEE_OTHER,
@@ -87,8 +85,7 @@ pub async fn logout(State(state): State<Arc<ConsoleState>>, headers: HeaderMap)
     if let Some(token) = extract_session_token(&headers) {
         state.sessions.remove(&token).await;
     }
-    let cookie =
-        "extenddb_session=; Path=/console; HttpOnly; SameSite=Strict; Max-Age=0".to_string();
+    let cookie = session_cookie("", 0, state.secure_cookies);
     (
         StatusCode::SEE_OTHER,
         [("location", "/console/login"), ("set-cookie", &cookie)],
@@ -96,6 +93,16 @@ pub async fn logout(State(state): State<Arc<ConsoleState>>, headers: HeaderMap)
         .into_response()
 }
 
+/// The `Set-Cookie` value for the console session. With `secure`, the cookie
+/// carries `Secure`, so a browser does not attach it to a plain `http://`
+/// request to the host (browsers exempt `localhost` from this rule).
+fn session_cookie(token: &str, max_age_secs: u32, secure: bool) -> String {
+    let secure = if secure { "; Secure" } else { "" };
+    format!(
+        "extenddb_session={token}; Path=/console; HttpOnly; SameSite=Strict; Max-Age={max_age_secs}{secure}"
+    )
+}
+
 fn login_html(error: Option<&str>, listen_url: &str) -> String {
     let error_html = error.map(html::alert_error).unwrap_or_default();
 
@@ -173,3 +180,64 @@ async fn try_iam_login(
         None
     }
 }
+
+#[cfg(test)]
+mod session_cookie_tests {
+    use super::session_cookie;
+
+    /// The `name=value` pair, which must come first, and the attributes after
+    /// it, sorted, since their order carries no meaning.
+    fn parts(cookie: &str) -> (&str, Vec<&str>) {
+        let mut parts = cookie.split(';').map(str::trim);
+        let pair = parts.next().unwrap_or_default();
+        let mut attributes: Vec<&str> = parts.collect();
+        attributes.sort_unstable();
+        (pair, attributes)
+    }
+
+    #[test]
+    fn a_tls_server_marks_the_session_cookie_secure() {
+        let login = session_cookie("t0k", 28800, true);
+        let (pair, attributes) = parts(&login);
+        assert_eq!(pair, "extenddb_session=t0k");
+        assert_eq!(
+            attributes,
+            [
+                "HttpOnly",
+                "Max-Age=28800",
+                "Path=/console",
+                "SameSite=Strict",
+                "Secure"
+            ]
+        );
+        let logout = session_cookie("", 0, true);
+        let (pair, attributes) = parts(&logout);
+        assert_eq!(pair, "extenddb_session=");
+        assert_eq!(
+            attributes,
+            [
+                "HttpOnly",
+                "Max-Age=0",
+                "Path=/console",
+                "SameSite=Strict",
+                "Secure"
+            ]
+        );
+    }
+
+    /// Dev mode serves plain HTTP, where `Secure` protects nothing, and an
+    /// HTTP client that does not treat the loopback origin as secure, such as
+    /// the Python `requests` client the console tests use, would not send the
+    /// cookie back.
+    #[test]
+    fn a_plain_http_server_leaves_secure_off() {
+        for cookie in [
+            session_cookie("t0k", 28800, false),
+            session_cookie("", 0, false),
+        ] {
+            let (_, attributes) = parts(&cookie);
+            assert!(!attributes.contains(&"Secure"), "{cookie}");
+            assert!(attributes.contains(&"HttpOnly") && attributes.contains(&"SameSite=Strict"));
+        }
+    }
+}
diff --git a/crates/server/src/lib.rs b/crates/server/src/lib.rs
index f608c74d7..035c35996 100755
--- a/crates/server/src/lib.rs
+++ b/crates/server/src/lib.rs
@@ -204,6 +204,7 @@ pub async fn start_server(
             docs_store: docs_store.clone(),
             auth_cache: auth_cache_for_console,
             metrics: metrics_for_console,
+            secure_cookies: tls_enabled,
         });
         let console_router = console::router().with_state(console_state);
         app = app
diff --git a/docs/manuals/10-security-model.md b/docs/manuals/10-security-model.md
index bb7a1c75d..97c619277 100755
--- a/docs/manuals/10-security-model.md
+++ b/docs/manuals/10-security-model.md
@@ -169,7 +169,7 @@ Replace the certificate and key files, then restart extenddb. There is no hot-re
 The management web console (`/console/*`) implements:
 
 - **CSRF protection**: Unique tokens generated per session, injected into all forms via JavaScript, validated on every POST handler
-- **Session management**: Server-side sessions with 8-hour expiry, HttpOnly cookies with `SameSite=Strict` and `Path=/console`
+- **Session management**: Server-side sessions with 8-hour expiry, HttpOnly and `Secure` cookies with `SameSite=Strict` and `Path=/console` (a dev-mode build serves plain HTTP and leaves `Secure` off)
 - **Security headers**: X-Content-Type-Options (nosniff), X-Frame-Options (DENY), Referrer-Policy (strict-origin-when-cross-origin)
 - **HSTS**: Sent automatically (TLS is always enabled)
 - **Login rate limiting**: Failed login attempts are tracked per user. Excessive failures trigger account lockout.
diff --git a/tests/test_console_integration.py b/tests/test_console_integration.py
index 402d9b2d4..e4ca9acc4 100755
--- a/tests/test_console_integration.py
+++ b/tests/test_console_integration.py
@@ -141,12 +141,19 @@ def setup(self, auth_env):
         self.admin_user = auth_env[1]
         self.admin_pass = auth_env[2]
 
+    def _assert_secure_matches_scheme(self, set_cookie: str) -> None:
+        """The session cookie carries Secure exactly when the console is served
+        over HTTPS (dev mode serves plain HTTP)."""
+        attrs = [a.strip() for a in set_cookie.split(";")]
+        assert ("Secure" in attrs) == self.endpoint.startswith("https://"), set_cookie
+
     def test_login_redirects_to_dashboard(self):
         client = ConsoleClient(self.endpoint)
         resp = client.login(self.admin_user, self.admin_pass)
         assert resp.status_code == 303
         assert "/console" in resp.headers.get("location", "")
         assert "extenddb_session=" in resp.headers.get("set-cookie", "")
+        self._assert_secure_matches_scheme(resp.headers.get("set-cookie", ""))
 
     def test_login_invalid_credentials(self):
         client = ConsoleClient(self.endpoint)
@@ -161,6 +168,7 @@ def test_logout_clears_session(self):
         resp = client.logout()
         assert resp.status_code == 303
         assert "/console/login" in resp.headers.get("location", "")
+        self._assert_secure_matches_scheme(resp.headers.get("set-cookie", ""))
         # After logout, accessing dashboard should redirect to login.
         resp = client.get("")
         assert resp.status_code == 303