diff --git a/src/Http/RestClient.php b/src/Http/RestClient.php
index 57519f61..7ee0bc0f 100644
--- a/src/Http/RestClient.php
+++ b/src/Http/RestClient.php
@@ -6,6 +6,7 @@
 
 use GuzzleHttp\Client;
 use GuzzleHttp\Psr7\Request;
+use HelpScout\Api\ApiClient;
 use HelpScout\Api\Entity\Extractable;
 use HelpScout\Api\Http\Hal\HalDeserializer;
 use HelpScout\Api\Http\Hal\HalResource;
@@ -58,10 +59,13 @@ public function getAuthHeader(): array
     /**
      * @return array
      */
-    protected function getDefaultHeaders(): array
+    public function getDefaultHeaders(): array
     {
         return array_merge(
-            ['Content-Type' => self::CONTENT_TYPE],
+            [
+                'Content-Type' => self::CONTENT_TYPE,
+                'User-Agent' => sprintf(self::CLIENT_USER_AGENT, ApiClient::CLIENT_VERSION, phpversion()),
+            ],
             $this->getAuthHeader()
         );
     }
diff --git a/tests/Http/RestClientTest.php b/tests/Http/RestClientTest.php
index c6a39b69..e1018bb1 100644
--- a/tests/Http/RestClientTest.php
+++ b/tests/Http/RestClientTest.php
@@ -9,6 +9,7 @@
 use GuzzleHttp\Exception\ServerException;
 use GuzzleHttp\Psr7\Request;
 use GuzzleHttp\Psr7\Response;
+use HelpScout\Api\ApiClient;
 use HelpScout\Api\Http\Auth\ClientCredentials;
 use HelpScout\Api\Http\Auth\LegacyCredentials;
 use HelpScout\Api\Http\Auth\NullCredentials;
@@ -34,6 +35,26 @@ public function setUp()
         $this->authenticator = \Mockery::mock(Authenticator::class);
     }
 
+    public function testDefaultHeaders()
+    {
+        $this->authenticator->shouldReceive('getAuthHeader')->andReturn([
+            'Authorization' => 'Bearer 123abc',
+        ]);
+
+        $restClient = new RestClient($this->methodsClient, $this->authenticator);
+
+        $headers = $restClient->getDefaultHeaders();
+
+        $this->assertArrayHasKey('Content-Type', $headers);
+        $this->assertEquals(RestClient::CONTENT_TYPE, $headers['Content-Type']);
+
+        $this->assertArrayHasKey('User-Agent', $headers);
+        $this->assertEquals('Help Scout PHP API Client/'.ApiClient::CLIENT_VERSION.' (PHP '.phpversion().')', $headers['User-Agent']);
+
+        $this->assertArrayHasKey('Authorization', $headers);
+        $this->assertEquals('Bearer 123abc', $headers['Authorization']);
+    }
+
     public function testRunReport()
     {
         $params = new ParameterBag([]);