diff --git a/README.md b/README.md
index 509810f..ba55f15 100644
--- a/README.md
+++ b/README.md
@@ -223,7 +223,9 @@ $gql = $builder->getQuery();
 # Constructing The Client
 
 A Client object can easily be instantiated by providing the GraphQL endpoint
-URL. The Client constructor also receives an optional "authorizationHeaders"
+URL. 
+
+The Client constructor also receives an optional "authorizationHeaders"
 array, which can be used to add authorization headers to all requests being sent
 to the GraphQL server.
 
@@ -236,6 +238,33 @@ $client = new Client(
 );
 ```
 
+
+The Client constructor also receives an optional "httpOptions" array, which **overrides** the "authorizationHeaders" and can be used to add custom [Guzzle HTTP Client request options](https://guzzle.readthedocs.io/en/latest/request-options.html).
+
+Example:
+
+```
+$client = new Client(
+    'http://api.graphql.com',
+    [],
+    [ 
+        'connect_timeout' => 5,
+        'timeout' => 5,
+        'headers' => [
+            'Authorization' => 'Basic xyz'
+            'User-Agent' => 'testing/1.0',
+        ],
+        'proxy' => [
+                'http'  => 'tcp://localhost:8125', // Use this proxy with "http"
+                'https' => 'tcp://localhost:9124', // Use this proxy with "https",
+                'no' => ['.mit.edu', 'foo.com']    // Don't use a proxy with these
+        ],
+        'cert' => ['/path/server.pem', 'password']
+        ...
+    ]
+);
+```
+
 # Running Queries
 
 ## Result Formatting
diff --git a/src/Client.php b/src/Client.php
index ed519fe..9cd6269 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -29,17 +29,25 @@ class Client
      */
     protected $httpClient;
 
+    /**
+     * @var array
+     */
+    protected $httpOptions;
+
+
     /**
      * Client constructor.
      *
      * @param string $endpointUrl
-     * @param array  $authorizationHeaders
+     * @param array $authorizationHeaders
+     * @param array $httpOptions
      */
-    public function __construct(string $endpointUrl, array $authorizationHeaders = [])
+    public function __construct(string $endpointUrl, array $authorizationHeaders = [], array $httpOptions = [])
     {
         $this->endpointUrl          = $endpointUrl;
         $this->authorizationHeaders = $authorizationHeaders;
         $this->httpClient           = new \GuzzleHttp\Client();
+        $this->httpOptions          = $httpOptions;
     }
 
     /**
@@ -77,6 +85,12 @@ public function runRawQuery(string $queryString, $resultsAsArray = false, array
         if (!empty($this->authorizationHeaders)) {
             $options['headers'] = $this->authorizationHeaders;
         }
+
+        // Set request options for \GuzzleHttp\Client
+        if (!empty($this->httpOptions)) {
+            $options = $this->httpOptions;
+        }
+
         $options['headers']['Content-Type'] = 'application/json';
 
         // Convert empty variables array to empty json object
diff --git a/tests/ClientTest.php b/tests/ClientTest.php
index 390b1de..b8342dc 100644
--- a/tests/ClientTest.php
+++ b/tests/ClientTest.php
@@ -7,6 +7,7 @@
 use GraphQL\QueryBuilder\QueryBuilder;
 use GraphQL\RawObject;
 use GuzzleHttp\Exception\ClientException;
+use GuzzleHttp\Exception\ConnectException;
 use GuzzleHttp\Exception\ServerException;
 use GuzzleHttp\Handler\MockHandler;
 use GuzzleHttp\HandlerStack;
@@ -58,6 +59,7 @@ public function testConstructClient()
         $mockHandler->append(new Response(200));
         $mockHandler->append(new Response(200));
         $mockHandler->append(new Response(200));
+        $mockHandler->append(new Response(200));
 
         $client = new MockClient('', $handler);
         $client->runRawQuery('query_string');
@@ -68,13 +70,16 @@ public function testConstructClient()
         $client = new MockClient('', $handler);
         $client->runRawQuery('query_string',  false, ['name' => 'val']);
 
+        $client = new MockClient('', $handler, ['Authorization' => 'Basic xyz'], ['headers' => [ 'Authorization' => 'Basic zyx', 'User-Agent' => 'test' ]]);
+        $client->runRawQuery('query_string');
+
         /** @var Request $firstRequest */
         $firstRequest = $container[0]['request'];
         $this->assertEquals('{"query":"query_string","variables":{}}', $firstRequest->getBody()->getContents());
 
         /** @var Request $thirdRequest */
         $thirdRequest = $container[1]['request'];
-        $this->assertNotNull($thirdRequest->getHeader('Authorization'));
+        $this->assertNotEmpty($thirdRequest->getHeader('Authorization'));
         $this->assertEquals(
             ['Basic xyz'],
             $thirdRequest->getHeader('Authorization')
@@ -83,6 +88,13 @@ public function testConstructClient()
         /** @var Request $secondRequest */
         $secondRequest = $container[2]['request'];
         $this->assertEquals('{"query":"query_string","variables":{"name":"val"}}', $secondRequest->getBody()->getContents());
+
+        /** @var Request $fourthRequest */
+        $fourthRequest = $container[3]['request'];
+        $this->assertNotEmpty($fourthRequest->getHeader('Authorization'));
+        $this->assertNotEmpty($fourthRequest->getHeader('User-Agent'));
+        $this->assertEquals(['Basic zyx'], $fourthRequest->getHeader('Authorization'));
+        $this->assertEquals(['test'], $fourthRequest->getHeader('User-Agent'));
     }
 
     /**
@@ -232,4 +244,14 @@ public function testInternalServerErrorResponse()
         $this->expectException(ServerException::class);
         $this->client->runRawQuery('');
     }
+
+    /**
+     * @covers \GraphQL\Client::runRawQuery
+     */
+    public function testConnectTimeoutResponse()
+    {
+        $this->mockHandler->append(new ConnectException('Time Out', new Request('post', '')));
+        $this->expectException(ConnectException::class);
+        $this->client->runRawQuery('');
+    }
 }
\ No newline at end of file
diff --git a/tests/MockClient.php b/tests/MockClient.php
index 6d14e9f..c908ec5 100644
--- a/tests/MockClient.php
+++ b/tests/MockClient.php
@@ -16,11 +16,12 @@ class MockClient extends Client
      *
      * @param string $endpointUrl
      * @param object $handler
-     * @param array  $authorizationHeaders
+     * @param array $authorizationHeaders
+     * @param array $httpOptions
      */
-    public function __construct(string $endpointUrl, $handler, array $authorizationHeaders = [])
+    public function __construct(string $endpointUrl, $handler, array $authorizationHeaders = [], array $httpOptions = [])
     {
-        parent::__construct($endpointUrl, $authorizationHeaders);
+        parent::__construct($endpointUrl, $authorizationHeaders, $httpOptions);
         $this->httpClient = new \GuzzleHttp\Client(['handler' => $handler]);
     }
 }
\ No newline at end of file