diff --git a/src/EventSource.php b/src/EventSource.php
index 6ec3c88..fd7d38c 100644
--- a/src/EventSource.php
+++ b/src/EventSource.php
@@ -77,8 +77,13 @@ class EventSource extends EventEmitter
     private $request;
     private $timer;
     private $reconnectTime = 3.0;
+    private $headers;
+    private $defaultHeaders = [
+        'Accept' => 'text/event-stream',
+        'Cache-Control' => 'no-cache'
+    ];
 
-    public function __construct($url, LoopInterface $loop, Browser $browser = null)
+    public function __construct($url, LoopInterface $loop, Browser $browser = null, array $headers = [])
     {
         $parts = parse_url($url);
         if (!isset($parts['scheme'], $parts['host']) || !in_array($parts['scheme'], array('http', 'https'))) {
@@ -92,16 +97,35 @@ public function __construct($url, LoopInterface $loop, Browser $browser = null)
         $this->loop = $loop;
         $this->url = $url;
 
+        $this->headers = $this->mergeHeaders($headers);
+
         $this->readyState = self::CONNECTING;
         $this->request();
     }
 
-    private function request()
+    private function mergeHeaders(array $headers = [])
     {
-        $headers = array(
-            'Accept' => 'text/event-stream',
-            'Cache-Control' => 'no-cache'
+        if ($headers === []) {
+            return $this->defaultHeaders;
+        }
+
+        // HTTP headers are case insensitive, we do not want to have different cases for the same (default) header
+        // Convert default headers to lowercase, to ease the custom headers potential override comparison
+        $loweredDefaults = array_change_key_case($this->defaultHeaders, CASE_LOWER);
+        foreach($headers as $k => $v) {
+            if (array_key_exists(strtolower($k), $loweredDefaults)) {
+                unset($headers[$k]);
+            }
+        }
+        return array_merge(
+            $headers,
+            $this->defaultHeaders
         );
+    }
+
+    private function request()
+    {
+        $headers = $this->headers;
         if ($this->lastEventId !== '') {
             $headers['Last-Event-ID'] = $this->lastEventId;
         }
diff --git a/tests/EventSourceTest.php b/tests/EventSourceTest.php
index e698a61..ad7fc2c 100644
--- a/tests/EventSourceTest.php
+++ b/tests/EventSourceTest.php
@@ -51,6 +51,48 @@ public function testConstructorCanBeCalledWithoutBrowser()
         $this->assertInstanceOf('Clue\React\Buzz\Browser', $browser);
     }
 
+        
+    public function testConstructorCanBeCalledWithoutCustomHeaders()
+    {
+        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+
+        $es = new EventSource('http://example.valid', $loop);
+
+        $ref = new ReflectionProperty($es, 'headers');
+        $ref->setAccessible(true);
+        $headers = $ref->getValue($es);
+
+        $ref = new ReflectionProperty($es, 'defaultHeaders');
+        $ref->setAccessible(true);
+        $defaultHeaders = $ref->getValue($es);
+        
+        $this->assertEquals($defaultHeaders, $headers);
+    }
+
+    public function testConstructorCanBeCalledWithCustomHeaders()
+    {
+        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+
+        $es = new EventSource('http://example.valid', $loop, null, array(
+            'x-custom' => '1234',
+            'Cache-Control' => 'only-if-cached',
+            'ACCEPT' => 'no-store',
+            'cache-control' => 'none'
+        ));
+
+        $ref = new ReflectionProperty($es, 'headers');
+        $ref->setAccessible(true);
+        $headers = $ref->getValue($es);
+
+        // Could have used the defaultHeaders property on EventSource, 
+        // but this ensures the defaults are not altered by hardcoding their values in this test 
+        $this->assertEquals(array(
+            'Accept' => 'text/event-stream',
+            'Cache-Control' => 'no-cache',
+            'x-custom' => '1234'
+        ), $headers);
+    }
+
     public function testConstructorWillSendGetRequestThroughGivenBrowser()
     {
         $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();