diff --git a/src/OAuth2/Grant/AuthCode.php b/src/OAuth2/Grant/AuthCode.php
index b0edc0b0..67dc2234 100644
--- a/src/OAuth2/Grant/AuthCode.php
+++ b/src/OAuth2/Grant/AuthCode.php
@@ -42,6 +42,12 @@ class AuthCode implements GrantTypeInterface {
      */
     protected $authServer = null;
 
+    /**
+     * Access token expires in override
+     * @var int
+     */
+    protected $expiresIn = null;
+
     /**
      * Constructor
      * @param AuthServer $authServer AuthServer instance
@@ -70,6 +76,16 @@ class AuthCode implements GrantTypeInterface {
         return $this->responseType;
     }
 
+    /**
+     * Override the default access token expire time
+     * @param int $expiresIn
+     * @return void
+     */
+    public function setExpiresIn($expiresIn)
+    {
+        $this->expiresIn = $expiresIn;
+    }
+
     /**
      * Check authorise parameters
      *
@@ -222,8 +238,8 @@ class AuthCode implements GrantTypeInterface {
         // A session ID was returned so update it with an access token and remove the authorisation code
 
         $accessToken = SecureKey::make();
-        $accessTokenExpires = time() + $this->authServer->getExpiresIn();
-        $accessTokenExpiresIn = $this->authServer->getExpiresIn();
+        $accessTokenExpiresIn = ($this->expiresIn !== null) ? $this->expiresIn : $this->authServer->getExpiresIn();
+        $accessTokenExpires = time() + $accessTokenExpiresIn;
 
         // Remove the auth code
         $this->authServer->getStorage('session')->removeAuthCode($session['id']);
diff --git a/src/OAuth2/Grant/ClientCredentials.php b/src/OAuth2/Grant/ClientCredentials.php
index 4a520ee7..5d2a48a9 100644
--- a/src/OAuth2/Grant/ClientCredentials.php
+++ b/src/OAuth2/Grant/ClientCredentials.php
@@ -42,6 +42,12 @@ class ClientCredentials implements GrantTypeInterface {
      */
     protected $authServer = null;
 
+    /**
+     * Access token expires in override
+     * @var int
+     */
+    protected $expiresIn = null;
+
     /**
      * Constructor
      * @param AuthServer $authServer AuthServer instance
@@ -70,6 +76,16 @@ class ClientCredentials implements GrantTypeInterface {
         return $this->responseType;
     }
 
+    /**
+     * Override the default access token expire time
+     * @param int $expiresIn
+     * @return void
+     */
+    public function setExpiresIn($expiresIn)
+    {
+        $this->expiresIn = $expiresIn;
+    }
+
     /**
      * Complete the client credentials grant
      * @param  null|array $inputParams
@@ -126,9 +142,8 @@ class ClientCredentials implements GrantTypeInterface {
 
         // Generate an access token
         $accessToken = SecureKey::make();
-
-        $accessTokenExpires = time() + $this->authServer->getExpiresIn();
-        $accessTokenExpiresIn = $this->authServer->getExpiresIn();
+        $accessTokenExpiresIn = ($this->expiresIn !== null) ? $this->expiresIn : $this->authServer->getExpiresIn();
+        $accessTokenExpires = time() + $accessTokenExpiresIn;
 
         // Delete any existing sessions just to be sure
         $this->authServer->getStorage('session')->deleteSession($authParams['client_id'], 'client', $authParams['client_id']);
diff --git a/src/OAuth2/Grant/Password.php b/src/OAuth2/Grant/Password.php
index b8d098db..dbc94eb9 100644
--- a/src/OAuth2/Grant/Password.php
+++ b/src/OAuth2/Grant/Password.php
@@ -48,6 +48,12 @@ class Password implements GrantTypeInterface {
      */
     protected $authServer = null;
 
+    /**
+     * Access token expires in override
+     * @var int
+     */
+    protected $expiresIn = null;
+
     /**
      * Constructor
      * @param AuthServer $authServer AuthServer instance
@@ -76,6 +82,16 @@ class Password implements GrantTypeInterface {
         return $this->responseType;
     }
 
+    /**
+     * Override the default access token expire time
+     * @param int $expiresIn
+     * @return void
+     */
+    public function setExpiresIn($expiresIn)
+    {
+        $this->expiresIn = $expiresIn;
+    }
+
     /**
      * Set the callback to verify a user's username and password
      * @param function $callback The callback function
@@ -169,8 +185,8 @@ class Password implements GrantTypeInterface {
 
         // Generate an access token
         $accessToken = SecureKey::make();
-        $accessTokenExpires = time() + $this->authServer->getExpiresIn();
-        $accessTokenExpiresIn = $this->authServer->getExpiresIn();
+        $accessTokenExpiresIn = ($this->expiresIn !== null) ? $this->expiresIn : $this->authServer->getExpiresIn();
+        $accessTokenExpires = time() + $accessTokenExpiresIn;
 
         // Delete any existing sessions just to be sure
         $this->authServer->getStorage('session')->deleteSession($authParams['client_id'], 'user', $userId);
diff --git a/src/OAuth2/Grant/RefreshToken.php b/src/OAuth2/Grant/RefreshToken.php
index 538d75bd..586c482f 100644
--- a/src/OAuth2/Grant/RefreshToken.php
+++ b/src/OAuth2/Grant/RefreshToken.php
@@ -42,6 +42,12 @@ class RefreshToken implements GrantTypeInterface {
      */
     protected $authServer = null;
 
+    /**
+     * Access token expires in override
+     * @var int
+     */
+    protected $expiresIn = null;
+
     /**
      * Constructor
      * @param AuthServer $authServer AuthServer instance
@@ -70,6 +76,16 @@ class RefreshToken implements GrantTypeInterface {
         return $this->responseType;
     }
 
+    /**
+     * Override the default access token expire time
+     * @param int $expiresIn
+     * @return void
+     */
+    public function setExpiresIn($expiresIn)
+    {
+        $this->expiresIn = $expiresIn;
+    }
+
     /**
      * Complete the refresh token grant
      * @param  null|array $inputParams
@@ -116,8 +132,8 @@ class RefreshToken implements GrantTypeInterface {
 
         // Generate new tokens and associate them to the session
         $accessToken = SecureKey::make();
-        $accessTokenExpires = time() + $this->authServer->getExpiresIn();
-        $accessTokenExpiresIn = $this->authServer->getExpiresIn();
+        $accessTokenExpiresIn = ($this->expiresIn !== null) ? $this->expiresIn : $this->authServer->getExpiresIn();
+        $accessTokenExpires = time() + $accessTokenExpiresIn;
         $refreshToken = SecureKey::make();
 
         $newAccessTokenId = $this->authServer->getStorage('session')->associateAccessToken($accessTokenDetails['session_id'], $accessToken, $accessTokenExpires);