diff --git a/src/Illuminate/Http/Client/PendingRequest.php b/src/Illuminate/Http/Client/PendingRequest.php
index a3a022c352f3..cfab639cf511 100644
--- a/src/Illuminate/Http/Client/PendingRequest.php
+++ b/src/Illuminate/Http/Client/PendingRequest.php
@@ -19,6 +19,7 @@
 use Illuminate\Support\Arr;
 use Illuminate\Support\Collection;
 use Illuminate\Support\Str;
+use Illuminate\Support\Stringable;
 use Illuminate\Support\Traits\Conditionable;
 use Illuminate\Support\Traits\Macroable;
 use JsonSerializable;
@@ -1035,10 +1036,12 @@ protected function sendRequest(string $method, string $url, array $options = [])
             $this->transferStats = $transferStats;
         };
 
-        return $this->buildClient()->$clientMethod($method, $url, $this->mergeOptions([
+        $mergedOptions = $this->normalizeRequestOptions($this->mergeOptions([
             'laravel_data' => $laravelData,
             'on_stats' => $onStats,
         ], $options));
+
+        return $this->buildClient()->$clientMethod($method, $url, $mergedOptions);
     }
 
     /**
@@ -1076,6 +1079,25 @@ protected function parseRequestData($method, $url, array $options)
         return is_array($laravelData) ? $laravelData : [];
     }
 
+    /**
+     * Normalize the given request options.
+     *
+     * @param  array  $options
+     * @return array
+     */
+    protected function normalizeRequestOptions(array $options)
+    {
+        foreach ($options as $key => $value) {
+            $options[$key] = match (true) {
+                is_array($value) => $this->normalizeRequestOptions($value),
+                $value instanceof Stringable => $value->toString(),
+                default => $value,
+            };
+        }
+
+        return $options;
+    }
+
     /**
      * Populate the given response with additional data.
      *
diff --git a/tests/Http/HttpClientTest.php b/tests/Http/HttpClientTest.php
index c2056867c970..cd3f529202ba 100644
--- a/tests/Http/HttpClientTest.php
+++ b/tests/Http/HttpClientTest.php
@@ -481,6 +481,57 @@ public function toArray(): array
         });
     }
 
+    public function testCanSendJsonDataWithStringable()
+    {
+        $this->factory->fake();
+
+        $this->factory->withHeaders([
+            'X-Test-Header' => 'foo',
+            'X-Test-ArrayHeader' => ['bar', 'baz'],
+        ])->post('http://foo.com/json', [
+            'name' => Str::of('Taylor'),
+        ]);
+
+        $this->factory->assertSent(function (Request $request) {
+            return $request->url() === 'http://foo.com/json' &&
+                   $request->hasHeader('Content-Type', 'application/json') &&
+                   $request->hasHeader('X-Test-Header', 'foo') &&
+                   $request->hasHeader('X-Test-ArrayHeader', ['bar', 'baz']) &&
+                   $request['name'] === 'Taylor';
+        });
+    }
+
+    public function testCanSendFormDataWithStringable()
+    {
+        $this->factory->fake();
+
+        $this->factory->asForm()->post('http://foo.com/form', [
+            'name' => Str::of('Taylor'),
+            'title' => 'Laravel Developer',
+        ]);
+
+        $this->factory->assertSent(function (Request $request) {
+            return $request->url() === 'http://foo.com/form' &&
+                   $request->hasHeader('Content-Type', 'application/x-www-form-urlencoded') &&
+                   $request['name'] === 'Taylor';
+        });
+    }
+
+    public function testCanSendFormDataWithStringableInArrays()
+    {
+        $this->factory->fake();
+
+        $this->factory->asForm()->post('http://foo.com/form', [
+            'posts' => [['title' => Str::of('Taylor')]],
+        ]);
+
+        $this->factory->assertSent(function (Request $request) {
+            return $request->url() === 'http://foo.com/form' &&
+                   $request->hasHeader('Content-Type', 'application/x-www-form-urlencoded') &&
+                   $request['posts'][0]['title'] === 'Taylor';
+        });
+    }
+
     public function testRecordedCallsAreEmptiedWhenFakeIsCalled()
     {
         $this->factory->fake([
@@ -800,6 +851,32 @@ public function testWithQueryParametersAllowsOverridingParameterOnRequest()
         });
     }
 
+    public function testWithStringableQueryParameters()
+    {
+        $this->factory->fake();
+
+        $this->factory->withQueryParameters(
+            ['foo' => Str::of('bar'),]
+        )->get('https://laravel.com');
+
+        $this->factory->assertSent(function (Request $request) {
+            return $request->url() === 'https://laravel.com?foo=bar';
+        });
+    }
+
+    public function testWithArrayStringableQueryParameters()
+    {
+        $this->factory->fake();
+
+        $this->factory->withQueryParameters(
+            ['foo' => ['bar', Str::of('baz')]],
+        )->get('https://laravel.com');
+
+        $this->factory->assertSent(function (Request $request) {
+            return $request->url() === 'https://laravel.com?foo%5B0%5D=bar&foo%5B1%5D=baz';
+        });
+    }
+
     public function testGetWithArrayQueryParam()
     {
         $this->factory->fake();