diff --git a/src/League/OAuth2/Server/Entities/AbstractToken.php b/src/League/OAuth2/Server/Entities/AbstractToken.php
new file mode 100644
index 00000000..ad3374d5
--- /dev/null
+++ b/src/League/OAuth2/Server/Entities/AbstractToken.php
@@ -0,0 +1,188 @@
+<?php
+
+namespace League\OAuth2\Server\Entities;
+
+use League\OAuth2\Server\Storage\SessionStorageInterface;
+use Symfony\Component\HttpFoundation\ParameterBag;
+use League\OAuth2\Server\Util\SecureKey;
+
+abstract class AbstractToken
+{
+    /**
+     * Access token ID
+     * @var string
+     */
+    protected $id = null;
+
+    /**
+     * Access token storage
+     * @var \League\OAuth2\Server\Storage\AccessTokenInterface
+     */
+    protected $storage = null;
+
+    /**
+     * Session storage
+     * @var \League\OAuth2\Server\Storage\SessionInterface
+     */
+    protected $sessionStorage = null;
+
+    /**
+     * Associated session
+     * @var \League\OAuth2\Server\Session
+     */
+    protected $session = null;
+
+    /**
+     * Session scopes
+     * @var \Symfony\Component\HttpFoundation\ParameterBag
+     */
+    protected $scopes = null;
+
+    /**
+     * __construct
+     * @param mixed $storage
+     * @return self
+     */
+    public function __construct($storage)
+    {
+        $this->storage = $storage;
+        $this->scopes = new ParameterBag();
+        return $this;
+    }
+
+    /**
+     * Get storage
+     * @return AccessTokenInterface
+     */
+    public function getStorage()
+    {
+        return $this->storage;
+    }
+
+    /**
+     * Set session
+     * @param \League\OAuth2\Server\Session $session
+     * @return self
+     */
+    public function setSession(Session $session)
+    {
+        $this->session = $session;
+        return $this;
+    }
+
+    /**
+     * Get session
+     * @return \League\OAuth2\Server\Session
+     */
+    public function getSession()
+    {
+        return $this->session;
+    }
+
+    /**
+     * Set token TTL
+     * @param integer $ttl TTL in seconds
+     * @return self
+     */
+    public function setTTL($ttl = 0)
+    {
+        $this->ttl = $ttl;
+        return $this;
+    }
+
+    /**
+     * Get token TTL
+     * @return integer
+     */
+    public function getTTL()
+    {
+        return $this->ttl;
+    }
+
+    /**
+     * Set the creation timestamp
+     * @param integer $timestamp Unix timestamp
+     * @return self
+     */
+    public function setTimestamp($timestamp = 0)
+    {
+        $this->timestamp = $timestamp;
+    }
+
+    /**
+     * Get access token creation timestamp
+     * @return integer Unix timestamp
+     */
+    public function getTimestamp()
+    {
+        return $this->timestamp;
+    }
+
+    /**
+     * Return creation timestamp + TTL
+     * @return int
+     */
+    public function getExpireTime()
+    {
+        return $this->getTimestamp() + $this->getTTL();
+    }
+
+    /**
+     * Set access token ID
+     * @param string $id Token ID
+     * @return self
+     */
+    public function setId($id = null)
+    {
+        $this->id = ($id !== null) ? $id : SecureKey::make();
+        return $this;
+    }
+
+    /**
+     * Get the token ID
+     * @return string
+     */
+    public function getId()
+    {
+        return $this->id;
+    }
+
+    /**
+     * Associate a scope
+     * @param \League\OAuth2\Server\Entities\Scope $scope
+     * @return self
+     */
+    public function associateScope($scope)
+    {
+        if (!$this->scopes->has($scope->getId())) {
+            $this->scopes->set($scope->getId(), $scope);
+        }
+
+        return $this;
+    }
+
+    /**
+     * Check if access token has an associated scope
+     * @param string $scope Scope to check
+     * @return bool
+     */
+    public function hasScope($scope)
+    {
+        return $this->scopes->has($scope);
+    }
+
+    /**
+     * Return all associated scopes
+     * @return ParameterBag
+     */
+    public function getScopes()
+    {
+        return $this->scopes;
+    }
+
+    /**
+     * Save the token to the database
+     * @return self
+     */
+    abstract function save();
+}
diff --git a/src/League/OAuth2/Server/Entities/AccessToken.php b/src/League/OAuth2/Server/Entities/AccessToken.php
new file mode 100644
index 00000000..b0ce4bc0
--- /dev/null
+++ b/src/League/OAuth2/Server/Entities/AccessToken.php
@@ -0,0 +1,38 @@
+<?php
+
+namespace League\OAuth2\Server\Entities;
+
+use League\OAuth2\Server\Storage\SessionStorageInterface;
+use League\OAuth2\Server\Storage\AccessTokenInterface;
+use Symfony\Component\HttpFoundation\ParameterBag;
+use League\OAuth2\Server\Util\SecureKey;
+use League\OAuth2\Server\Exception\InvalidAccessTokenException;
+
+class AccessToken extends AbstractToken
+{
+    /**
+     * __construct
+     * @param AccessTokenInterface $storage
+     * @return self
+     */
+    public function __construct(AccessTokenInterface $storage)
+    {
+        parent::__construct($storage);
+    }
+
+    public function save()
+    {
+        $this->getStorage()->createAccessToken(
+            $this->getId(),
+            $this->getExpireTime(),
+            $this->getSession()->getId()
+        );
+
+        // Associate the scope with the token
+        foreach ($this->getScopes() as $scope) {
+            $this->getStorage()->associateScope($this->getId(), $scope->getId());
+        }
+
+        return $this;
+    }
+}
diff --git a/src/League/OAuth2/Server/Entities/Client.php b/src/League/OAuth2/Server/Entities/Client.php
new file mode 100644
index 00000000..59781892
--- /dev/null
+++ b/src/League/OAuth2/Server/Entities/Client.php
@@ -0,0 +1,58 @@
+<?php
+
+namespace League\OAuth2\Server\Entities;
+
+class Client
+{
+    protected $id = null;
+
+    protected $secret = null;
+
+    protected $name = null;
+
+    protected $redirectUri = null;
+
+    public function setId($id)
+    {
+        $this->id = $id;
+        return $this;
+    }
+
+    public function getId()
+    {
+        return $this->id;
+    }
+
+    public function setSecret($secret)
+    {
+        $this->secret = $secret;
+        return $this;
+    }
+
+    public function getSecret()
+    {
+        return $this->secret;
+    }
+
+    public function setName($name)
+    {
+        $this->name = $name;
+        return $this;
+    }
+
+    public function getName()
+    {
+        return $this->name;
+    }
+
+    public function setRedirectUri($redirectUri)
+    {
+        $this->redirectUri = $redirectUri;
+        return $this;
+    }
+
+    public function getRedirectUri()
+    {
+        return $this->redirectUri;
+    }
+}
\ No newline at end of file
diff --git a/src/League/OAuth2/Server/Entities/RefreshToken.php b/src/League/OAuth2/Server/Entities/RefreshToken.php
new file mode 100644
index 00000000..2900bec2
--- /dev/null
+++ b/src/League/OAuth2/Server/Entities/RefreshToken.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace League\OAuth2\Server\Entities;
+
+use League\OAuth2\Server\Storage\SessionStorageInterface;
+use League\OAuth2\Server\Storage\RefreshTokenInterface;
+use Symfony\Component\HttpFoundation\ParameterBag;
+use League\OAuth2\Server\Util\SecureKey;
+use League\OAuth2\Server\Exception\InvalidAccessTokenException;
+
+class RefreshToken extends AbstractToken
+{
+    protected $accessToken;
+
+    /**
+     * __construct
+     * @param RefreshTokenInterface $storage
+     * @return self
+     */
+    public function __construct(RefreshTokenInterface $storage)
+    {
+        parent::__construct($storage);
+    }
+
+    /**
+     * Associate an access token
+     * @param AccessToken $accessToken
+     * @return self
+     */
+    public function setAccessToken(AccessToken $accessToken)
+    {
+        $this->accessToken = $accessToken;
+        return $this;
+    }
+
+    /**
+     * Return access token
+     * @return AccessToken
+     */
+    public function getAccessToken()
+    {
+        return $this->accessToken;
+    }
+
+    /**
+     * (@inheritdoc)
+     */
+    public function save()
+    {
+        /*$this->getStorage()->createAccessToken(
+            $this->getId(),
+            $this->getExpireTime(),
+            $this->getAccessToken()->getId()
+        );
+
+        // Associate the scope with the token
+        foreach ($this->getScopes() as $scope) {
+            $this->getStorage()->associateScope($this->getId(), $scope->getId());
+        }*/
+    }
+}
diff --git a/src/League/OAuth2/Server/Entities/Scope.php b/src/League/OAuth2/Server/Entities/Scope.php
new file mode 100644
index 00000000..acbd86c4
--- /dev/null
+++ b/src/League/OAuth2/Server/Entities/Scope.php
@@ -0,0 +1,58 @@
+<?php
+
+namespace League\OAuth2\Server\Entities;
+
+class Scope
+{
+    protected $id = null;
+
+    protected $scope = null;
+
+    protected $name = null;
+
+    protected $description = null;
+
+    public function setId($id)
+    {
+        $this->id = $id;
+        return $this;
+    }
+
+    public function getId()
+    {
+        return $this->id;
+    }
+
+    public function setScope($scope)
+    {
+        $this->scope = $scope;
+        return $this;
+    }
+
+    public function getScope()
+    {
+        return $this->scope;
+    }
+
+    public function setName($name)
+    {
+        $this->name = $name;
+        return $this;
+    }
+
+    public function getName()
+    {
+        return $this->name;
+    }
+
+    public function setDescription($description)
+    {
+        $this->description = $description;
+        return $this;
+    }
+
+    public function getDescription()
+    {
+        return $this->description;
+    }
+}
\ No newline at end of file
diff --git a/src/League/OAuth2/Server/Entities/Session.php b/src/League/OAuth2/Server/Entities/Session.php
new file mode 100644
index 00000000..38b89877
--- /dev/null
+++ b/src/League/OAuth2/Server/Entities/Session.php
@@ -0,0 +1,188 @@
+<?php
+
+namespace League\OAuth2\Server\Entities;
+
+use OutOfBoundsException;
+use League\OAuth2\Server\Exception\OAuth2Exception;
+use League\OAuth2\Server\Storage\SessionInterface;
+use Symfony\Component\HttpFoundation\ParameterBag;
+
+class Session
+{
+    /**
+     * Session ID
+     * @var string
+     */
+    protected $id = null;
+
+    protected $clientId = null;
+
+    protected $ownerId = null;
+
+    protected $ownerType = null;
+
+    protected $authCode = null;
+
+    protected $accessToken = null;
+
+    protected $refreshToken = null;
+
+    /**
+     * Session storage
+     * @var \League\OAuth2\Server\Storage\SessionInterface
+     */
+    protected $storage = null;
+
+    /**
+     * Session scopes
+     * @var \Symfony\Component\HttpFoundation\ParameterBag
+     */
+    protected $scopes = null;
+
+    /**
+     * Constuctor
+     * @param SessionInterface $storage
+     * @return self
+     */
+    public function __construct(SessionInterface $storage)
+    {
+        $this->storage = $storage;
+        $this->scopes = new ParameterBag();
+        return $this;
+    }
+
+    /**
+     * Get storage
+     * @return SessionInterface
+     */
+    public function getStorage()
+    {
+        return $this->storage;
+    }
+
+    public function setId($id)
+    {
+        $this->id = $id;
+        return $this;
+    }
+
+    public function getId()
+    {
+        return $this->id;
+    }
+
+    /**
+     * Associate a scope
+     * @param \League\OAuth2\Server\Entities\Scope $scope
+     * @return self
+     */
+    public function associateScope($scope)
+    {
+        if (!$this->scopes->has($scope->getId())) {
+            $this->scopes->set($scope->getId(), $scope);
+        }
+
+        return $this;
+    }
+
+    /**
+     * Check if access token has an associated scope
+     * @param string $scope Scope to check
+     * @return bool
+     */
+    public function hasScope($scope)
+    {
+        return $this->scopes->has($scope);
+    }
+
+    public function getScopes()
+    {
+        return $this->scopes;
+    }
+
+    public function associateAccessToken(AccessToken $accessToken)
+    {
+        $this->accessToken = $accessToken;
+    }
+
+    public function associateRefreshToken(RefreshToken $refreshToken)
+    {
+        $this->refreshToken = $refreshToken;
+    }
+
+    public function associateAuthCode(AuthCode $authCode)
+    {
+        $this->authCode = $authCode;
+    }
+
+    /**
+     * Associate a client
+     * @param  League\OAuth2\Server\Client $client The client
+     * @return self
+     */
+    public function associateClient(Client $client)
+    {
+        $this->client = $client;
+
+        return $this;
+    }
+
+    /**
+     * Return client
+     * @return League\OAuth2\Server\Client
+     */
+    public function getClient()
+    {
+        return $this->client;
+    }
+
+    /**
+     * Set the session owner
+     * @param string $type The type of the owner (e.g. user, app)
+     * @param string $id   The ID of the owner
+     * @return self
+     */
+    public function setOwner($type, $id)
+    {
+        $this->ownerType = $type;
+        $this->ownerId = $id;
+
+        return $this;
+    }
+
+    /**
+     * Return session owner ID
+     * @return string
+     */
+    public function getOwnerId()
+    {
+        return $this->ownerId;
+    }
+
+    /**
+     * Return session owner type
+     * @return string
+     */
+    public function getOwnerType()
+    {
+        return $this->ownerType;
+    }
+
+    public function save()
+    {
+        // Save the session and get an ID
+        $id = $this->getStorage()->createSession(
+            $this->getOwnerType(),
+            $this->getOwnerId(),
+            $this->getClient()->getId(),
+            $this->getClient()->getRedirectUri()
+        );
+
+        $this->setId($id);
+
+        // Associate the scope with the session
+        foreach ($this->getScopes() as $scope) {
+            $this->getStorage()->associateScope($this->getId(), $scope->getId());
+        }
+    }
+}