diff --git a/src/Http/Client.php b/src/Http/Client.php
index 9e1fc81..8d268d3 100644
--- a/src/Http/Client.php
+++ b/src/Http/Client.php
@@ -231,7 +231,7 @@ public function recorded(callable $filterCallback = null): array
      *
      * @throws \Psr\Http\Client\ClientExceptionInterface If an error happens while processing the request.
      */
-    public function json(string $method, string $url, array $params = []): Response
+    public function json(string $method, string $url, array $params = [], array $headers = []): Response
     {
         $method = strtoupper($method);
 
@@ -240,6 +240,10 @@ public function json(string $method, string $url, array $params = []): Response
             ->withHeader('Content-Type', 'application/json')
             ->withHeader('Accept', 'application/json');
 
+        foreach ($headers as $key => $value) {
+            $request = $request->withHeader($key, $value);
+        }
+
         if ($method !== 'GET') {
             $request = $request->withBody($this->streamFactory->createStream(json_encode($params)));
         }
@@ -257,7 +261,7 @@ public function json(string $method, string $url, array $params = []): Response
      *
      * @throws \Psr\Http\Client\ClientExceptionInterface If an error happens while processing the request.
      */
-    public function form(string $method, string $url, array $params = []): Response
+    public function form(string $method, string $url, array $params = [], array $headers = []): Response
     {
         $method = strtoupper($method);
 
@@ -265,6 +269,10 @@ public function form(string $method, string $url, array $params = []): Response
             ->createRequest($method, $this->buildUrl($method, $url, $params))
             ->withHeader('Content-Type', 'application/x-www-form-urlencoded');
 
+        foreach ($headers as $key => $value) {
+            $request = $request->withHeader($key, $value);
+        }
+
         if ($method !== 'GET') {
             $request = $request->withBody($this->streamFactory->createStream(http_build_query($params)));
         }
diff --git a/tests/Client/FormTest.php b/tests/Client/FormTest.php
index 5e10229..8e7bd1a 100644
--- a/tests/Client/FormTest.php
+++ b/tests/Client/FormTest.php
@@ -130,4 +130,37 @@ public function making_a_non_get_request_with_options_puts_them_in_the_body(stri
 
         $testingClient->client->form($verb, $url, ['active' => 1, 'page' => 12]);
     }
+
+    /**
+     * @test
+     * @dataProvider httpVerbsProvider
+     */
+    public function can_provide_custom_headers(string $verb)
+    {
+        $url = 'https://example.com';
+
+        $testingClient = $this->createTestingClient();
+        $psr7Request = null;
+
+        $psr7Response = $this->expectSendRequest($testingClient, function (RequestInterface $request) use (
+            $url,
+            $verb,
+            &$psr7Request,
+        ) {
+            $this->assertSame('application/x-www-form-urlencoded', $request->getHeaderLine('Content-Type'));
+            $this->assertSame('Custom Value', $request->getHeaderLine('X-Custom-Header'));
+
+            $this->assertSame($verb, strtoupper($request->getMethod()));
+            $this->assertSame($url, (string) $request->getUri());
+
+            $psr7Request = $request;
+
+            return true;
+        });
+
+        $response = $testingClient->client->form($verb, $url, [], ['X-Custom-Header' => 'Custom Value']);
+
+        $this->assertSame($psr7Request, $response->toPsr7Request());
+        $this->assertSame($psr7Response, $response->toPsr7Response());
+    }
 }
diff --git a/tests/Client/JsonTest.php b/tests/Client/JsonTest.php
index 1cfe674..7ea0cfe 100644
--- a/tests/Client/JsonTest.php
+++ b/tests/Client/JsonTest.php
@@ -136,4 +136,38 @@ public function making_a_non_get_request_with_options_puts_them_in_the_body(stri
 
         $testingClient->client->json($verb, $url, ['active' => 1, 'page' => 12]);
     }
+
+    /**
+     * @test
+     * @dataProvider httpVerbsProvider
+     */
+    public function can_provide_custom_headers(string $verb)
+    {
+        $url = 'https://example.com';
+
+        $testingClient = $this->createTestingClient();
+        $psr7Request = null;
+
+        $psr7Response = $this->expectSendRequest($testingClient, function (RequestInterface $request) use (
+            $url,
+            $verb,
+            &$psr7Request,
+        ) {
+            $this->assertSame('application/json', $request->getHeaderLine('Content-Type'));
+            $this->assertSame('application/json', $request->getHeaderLine('Accept'));
+            $this->assertSame('Custom Value', $request->getHeaderLine('X-Custom-Header'));
+
+            $this->assertSame($verb, strtoupper($request->getMethod()));
+            $this->assertSame($url, (string) $request->getUri());
+
+            $psr7Request = $request;
+
+            return true;
+        });
+
+        $response = $testingClient->client->json($verb, $url, [], ['X-Custom-Header' => 'Custom Value']);
+
+        $this->assertSame($psr7Request, $response->toPsr7Request());
+        $this->assertSame($psr7Response, $response->toPsr7Response());
+    }
 }