diff --git a/codex-rs/login/src/auth/manager.rs b/codex-rs/login/src/auth/manager.rs
index 83681b6c0e44..bdd5951c9720 100644
--- a/codex-rs/login/src/auth/manager.rs
+++ b/codex-rs/login/src/auth/manager.rs
@@ -7,6 +7,10 @@ use serde::Serialize;
 use serial_test::serial;
 use std::env;
 use std::fmt::Debug;
+use std::fs::File;
+use std::fs::OpenOptions;
+#[cfg(unix)]
+use std::os::unix::fs::OpenOptionsExt;
 use std::path::Path;
 use std::path::PathBuf;
 use std::sync::Arc;
@@ -85,6 +89,8 @@ struct ChatgptAuthState {
 
 const TOKEN_REFRESH_INTERVAL: i64 = 8;
 const CHATGPT_ACCESS_TOKEN_REFRESH_WINDOW_MINUTES: i64 = 5;
+const CHATGPT_TOKEN_REFRESH_LOCK_FILENAME: &str = "chatgpt-token-refresh.lock";
+const CHATGPT_TOKEN_REFRESH_LOCK_POLL_INTERVAL_MS: u64 = 50;
 
 const REFRESH_TOKEN_EXPIRED_MESSAGE: &str = "Your access token could not be refreshed because your refresh token has expired. Please log out and sign in again.";
 const REFRESH_TOKEN_REUSED_MESSAGE: &str = "Your access token could not be refreshed because your refresh token was already used. Please log out and sign in again.";
@@ -1431,7 +1437,7 @@ impl AuthManager {
 
         let auth = self.auth_cached()?;
         if Self::should_refresh_proactively(&auth)
-            && let Err(err) = self.refresh_token().await
+            && let Err(err) = self.proactively_refresh_token().await
         {
             tracing::error!("Failed to refresh token: {}", err);
             return Some(auth);
@@ -1681,12 +1687,37 @@ impl AuthManager {
     /// can assume that some other instance already refreshed it. If the persisted
     /// token is the same as the cached, then ask the token authority to refresh.
     pub async fn refresh_token(&self) -> Result<(), RefreshTokenError> {
-        let _refresh_guard = self.refresh_lock.acquire().await.map_err(|_| {
+        let auth_before_wait = self.auth_cached();
+        let is_managed_chatgpt = matches!(auth_before_wait.as_ref(), Some(CodexAuth::Chatgpt(_)));
+        let _token_refresh_lock = if is_managed_chatgpt {
+            Some(self.acquire_chatgpt_token_refresh_lock().await?)
+        } else {
+            None
+        };
+        let _refresh_guard = self.acquire_refresh_guard().await?;
+        if is_managed_chatgpt
+            && !Self::auths_equal_for_refresh(
+                auth_before_wait.as_ref(),
+                self.auth_cached().as_ref(),
+            )
+        {
+            return Ok(());
+        }
+        self.refresh_token_after_guarded_reload().await
+    }
+
+    async fn acquire_refresh_guard(
+        &self,
+    ) -> Result<tokio::sync::SemaphorePermit<'_>, RefreshTokenError> {
+        self.refresh_lock.acquire().await.map_err(|_| {
             RefreshTokenError::Permanent(RefreshTokenFailedError::new(
                 RefreshTokenFailedReason::Other,
                 REFRESH_TOKEN_UNKNOWN_MESSAGE.to_string(),
             ))
-        })?;
+        })
+    }
+
+    async fn refresh_token_after_guarded_reload(&self) -> Result<(), RefreshTokenError> {
         let auth_before_reload = self.auth_cached();
         if auth_before_reload
             .as_ref()
@@ -1716,17 +1747,71 @@ impl AuthManager {
         }
     }
 
+    async fn proactively_refresh_token(&self) -> Result<(), RefreshTokenError> {
+        let _refresh_lock = self.acquire_chatgpt_token_refresh_lock().await?;
+        let _refresh_guard = self.acquire_refresh_guard().await?;
+        if !self
+            .auth_cached()
+            .as_ref()
+            .is_some_and(Self::should_refresh_proactively)
+        {
+            return Ok(());
+        }
+        self.refresh_token_after_guarded_reload().await
+    }
+
+    async fn acquire_chatgpt_token_refresh_lock(&self) -> Result<File, RefreshTokenError> {
+        let mut logged_wait = false;
+        loop {
+            if let Some(lock_file) = self.try_acquire_chatgpt_token_refresh_lock()? {
+                return Ok(lock_file);
+            }
+            if !logged_wait {
+                tracing::info!(
+                    "Waiting to refresh managed ChatGPT tokens because another process is already refreshing them."
+                );
+                logged_wait = true;
+            }
+            tokio::time::sleep(std::time::Duration::from_millis(
+                CHATGPT_TOKEN_REFRESH_LOCK_POLL_INTERVAL_MS,
+            ))
+            .await;
+        }
+    }
+
+    fn try_acquire_chatgpt_token_refresh_lock(&self) -> Result<Option<File>, RefreshTokenError> {
+        let lock_path = self.codex_home.join(CHATGPT_TOKEN_REFRESH_LOCK_FILENAME);
+        if let Some(parent) = lock_path.parent() {
+            std::fs::create_dir_all(parent).map_err(RefreshTokenError::Transient)?;
+        }
+
+        let mut options = OpenOptions::new();
+        options.read(true).write(true).create(true).truncate(false);
+        #[cfg(unix)]
+        {
+            options.mode(0o600);
+        }
+        let lock_file = options
+            .open(lock_path)
+            .map_err(RefreshTokenError::Transient)?;
+
+        match lock_file.try_lock() {
+            Ok(()) => Ok(Some(lock_file)),
+            Err(std::fs::TryLockError::WouldBlock) => Ok(None),
+            Err(err) => Err(RefreshTokenError::Transient(err.into())),
+        }
+    }
+
     /// Attempt to refresh the current auth token from the authority that issued
-    /// the token. On success, reloads the auth state from disk so other components
-    /// observe refreshed token. If the token refresh fails, returns the error to
-    /// the caller.
+    /// the token. Managed ChatGPT auth reuses tokens refreshed by another process
+    /// while waiting to serialize refresh-token rotation. On success, reloads the
+    /// auth state from disk so other components observe refreshed token. If the
+    /// token refresh fails, returns the error to the caller.
     pub async fn refresh_token_from_authority(&self) -> Result<(), RefreshTokenError> {
-        let _refresh_guard = self.refresh_lock.acquire().await.map_err(|_| {
-            RefreshTokenError::Permanent(RefreshTokenFailedError::new(
-                RefreshTokenFailedReason::Other,
-                REFRESH_TOKEN_UNKNOWN_MESSAGE.to_string(),
-            ))
-        })?;
+        if matches!(self.auth_cached(), Some(CodexAuth::Chatgpt(_))) {
+            return self.refresh_token().await;
+        }
+        let _refresh_guard = self.acquire_refresh_guard().await?;
         self.refresh_token_from_authority_impl().await
     }
 
diff --git a/codex-rs/login/tests/suite/auth_refresh.rs b/codex-rs/login/tests/suite/auth_refresh.rs
index c3d443a76569..7db7cd0e2d89 100644
--- a/codex-rs/login/tests/suite/auth_refresh.rs
+++ b/codex-rs/login/tests/suite/auth_refresh.rs
@@ -19,6 +19,7 @@ use pretty_assertions::assert_eq;
 use serde::Serialize;
 use serde_json::json;
 use std::ffi::OsString;
+use std::fs::File;
 use std::sync::Arc;
 use tempfile::TempDir;
 use wiremock::Mock;
@@ -254,6 +255,209 @@ async fn auth_skips_access_token_outside_refresh_window() -> Result<()> {
     Ok(())
 }
 
+#[serial_test::serial(auth_refresh)]
+#[tokio::test]
+async fn auth_waits_while_chatgpt_token_refresh_lock_is_held() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = MockServer::start().await;
+    Mock::given(method("POST"))
+        .and(path("/oauth/token"))
+        .respond_with(ResponseTemplate::new(200).set_body_json(json!({
+            "access_token": "new-access-token",
+            "refresh_token": "new-refresh-token"
+        })))
+        .expect(1)
+        .mount(&server)
+        .await;
+
+    let ctx = RefreshTokenTestContext::new(&server).await?;
+    let initial_last_refresh = Utc::now();
+    let expired_access_token = access_token_with_expiration(Utc::now() - Duration::minutes(1));
+    let initial_tokens = build_tokens(&expired_access_token, INITIAL_REFRESH_TOKEN);
+    let initial_auth = AuthDotJson {
+        auth_mode: Some(AuthMode::Chatgpt),
+        openai_api_key: None,
+        tokens: Some(initial_tokens.clone()),
+        last_refresh: Some(initial_last_refresh),
+        agent_identity: None,
+    };
+    ctx.write_auth(&initial_auth).await?;
+
+    let lock_file = ctx.hold_chatgpt_token_refresh_lock()?;
+
+    let auth_manager = Arc::clone(&ctx.auth_manager);
+    let refresh_task = tokio::spawn(async move { auth_manager.auth().await });
+
+    tokio::time::sleep(std::time::Duration::from_millis(100)).await;
+    assert!(
+        !refresh_task.is_finished(),
+        "auth should wait while another process holds the proactive refresh lock"
+    );
+    assert_eq!(ctx.load_auth()?, initial_auth);
+    let requests = server.received_requests().await.unwrap_or_default();
+    assert!(
+        requests.is_empty(),
+        "expected no refresh token requests before the proactive refresh lock is released"
+    );
+
+    drop(lock_file);
+    let cached_auth = refresh_task
+        .await
+        .context("proactive refresh task should join")?
+        .context("auth should stay cached after the lock is released")?;
+
+    let cached = cached_auth
+        .get_token_data()
+        .context("token data should refresh")?;
+    assert_eq!(cached.access_token, "new-access-token");
+    assert_eq!(cached.refresh_token, "new-refresh-token");
+    let stored = ctx.load_auth()?;
+    let tokens = stored.tokens.as_ref().context("tokens should exist")?;
+    assert_eq!(tokens.access_token, "new-access-token");
+    assert_eq!(tokens.refresh_token, "new-refresh-token");
+    server.verify().await;
+
+    Ok(())
+}
+
+#[serial_test::serial(auth_refresh)]
+#[tokio::test]
+async fn concurrent_auth_requests_share_one_proactive_refresh() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = MockServer::start().await;
+    Mock::given(method("POST"))
+        .and(path("/oauth/token"))
+        .respond_with(ResponseTemplate::new(200).set_body_json(json!({
+            "access_token": "new-access-token",
+            "refresh_token": "new-refresh-token"
+        })))
+        .expect(1)
+        .mount(&server)
+        .await;
+
+    let ctx = RefreshTokenTestContext::new(&server).await?;
+    let near_expiry_access_token = access_token_with_expiration(Utc::now() + Duration::minutes(4));
+    let initial_tokens = build_tokens(&near_expiry_access_token, INITIAL_REFRESH_TOKEN);
+    ctx.write_auth(&AuthDotJson {
+        auth_mode: Some(AuthMode::Chatgpt),
+        openai_api_key: None,
+        tokens: Some(initial_tokens.clone()),
+        last_refresh: Some(Utc::now()),
+        agent_identity: None,
+    })
+    .await?;
+
+    let lock_file = ctx.hold_chatgpt_token_refresh_lock()?;
+    let first_manager = Arc::clone(&ctx.auth_manager);
+    let first = tokio::spawn(async move { first_manager.auth().await });
+    let second_manager = Arc::clone(&ctx.auth_manager);
+    let second = tokio::spawn(async move { second_manager.auth().await });
+
+    tokio::time::sleep(std::time::Duration::from_millis(100)).await;
+    assert!(!first.is_finished());
+    assert!(!second.is_finished());
+    drop(lock_file);
+
+    let (first_auth, second_auth) = tokio::join!(first, second);
+    let refreshed_tokens = TokenData {
+        access_token: "new-access-token".to_string(),
+        refresh_token: "new-refresh-token".to_string(),
+        ..initial_tokens
+    };
+    for auth in [first_auth, second_auth] {
+        let auth = auth
+            .context("proactive refresh task should join")?
+            .context("auth should stay cached after the lock is released")?;
+        assert_eq!(
+            auth.get_token_data().context("token data should refresh")?,
+            refreshed_tokens
+        );
+    }
+    assert_eq!(
+        ctx.load_auth()?.tokens.context("tokens should exist")?,
+        refreshed_tokens
+    );
+    server.verify().await;
+
+    Ok(())
+}
+
+#[serial_test::serial(auth_refresh)]
+#[tokio::test]
+async fn refresh_token_reloads_managed_auth_after_waiting_for_token_refresh_lock() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = MockServer::start().await;
+    Mock::given(method("POST"))
+        .and(path("/oauth/token"))
+        .respond_with(ResponseTemplate::new(200).set_body_json(json!({
+            "access_token": "unexpected-access-token",
+            "refresh_token": "unexpected-refresh-token"
+        })))
+        .expect(0)
+        .mount(&server)
+        .await;
+
+    let ctx = RefreshTokenTestContext::new(&server).await?;
+    let initial_last_refresh = Utc::now();
+    let initial_tokens = build_tokens(INITIAL_ACCESS_TOKEN, INITIAL_REFRESH_TOKEN);
+    ctx.write_auth(&AuthDotJson {
+        auth_mode: Some(AuthMode::Chatgpt),
+        openai_api_key: None,
+        tokens: Some(initial_tokens),
+        last_refresh: Some(initial_last_refresh),
+        agent_identity: None,
+    })
+    .await?;
+
+    let lock_file = ctx.hold_chatgpt_token_refresh_lock()?;
+
+    let auth_manager = Arc::clone(&ctx.auth_manager);
+    let refresh_task =
+        tokio::spawn(async move { auth_manager.refresh_token_from_authority().await });
+
+    tokio::time::sleep(std::time::Duration::from_millis(100)).await;
+    assert!(
+        !refresh_task.is_finished(),
+        "managed refresh should wait while another process holds the token refresh lock"
+    );
+
+    let disk_tokens = build_tokens("disk-access-token", "disk-refresh-token");
+    let disk_auth = AuthDotJson {
+        auth_mode: Some(AuthMode::Chatgpt),
+        openai_api_key: None,
+        tokens: Some(disk_tokens.clone()),
+        last_refresh: Some(initial_last_refresh),
+        agent_identity: None,
+    };
+    save_auth(
+        ctx.codex_home.path(),
+        &disk_auth,
+        AuthCredentialsStoreMode::File,
+    )?;
+
+    drop(lock_file);
+    refresh_task
+        .await
+        .context("managed refresh task should join")?
+        .context("managed refresh should use newly persisted auth")?;
+
+    let stored = ctx.load_auth()?;
+    assert_eq!(stored, disk_auth);
+    let cached = ctx
+        .auth_manager
+        .auth_cached()
+        .context("auth should be cached")?
+        .get_token_data()
+        .context("token data should reload")?;
+    assert_eq!(cached, disk_tokens);
+    server.verify().await;
+
+    Ok(())
+}
+
 #[serial_test::serial(auth_refresh)]
 #[tokio::test]
 async fn refresh_token_skips_refresh_when_auth_changed() -> Result<()> {
@@ -1106,6 +1310,18 @@ impl RefreshTokenTestContext {
         self.auth_manager.reload().await;
         Ok(())
     }
+
+    fn hold_chatgpt_token_refresh_lock(&self) -> Result<File> {
+        let lock_path = self.codex_home.path().join("chatgpt-token-refresh.lock");
+        let lock_file = File::options()
+            .read(true)
+            .write(true)
+            .create(true)
+            .truncate(false)
+            .open(lock_path)?;
+        lock_file.try_lock()?;
+        Ok(lock_file)
+    }
 }
 
 struct EnvGuard {