diff --git a/src/Illuminate/Http/Request.php b/src/Illuminate/Http/Request.php
index d355cab241d2..5ede629fc063 100644
--- a/src/Illuminate/Http/Request.php
+++ b/src/Illuminate/Http/Request.php
@@ -63,6 +63,13 @@ class Request extends SymfonyRequest implements Arrayable, ArrayAccess
      */
     protected $routeResolver;
 
+    /**
+     * The cached Accept header value used to detect changes.
+     *
+     * @var string|null
+     */
+    protected $cachedAcceptHeader;
+
     /**
      * Create a new Illuminate HTTP request from server variables.
      *
@@ -812,4 +819,23 @@ public function __get($key)
     {
         return Arr::get($this->all(), $key, fn () => $this->route($key));
     }
+
+    /**
+     * {@inheritdoc}
+     *
+     * Override to clear cache when Accept header changes.
+     */
+    #[\Override]
+    public function getAcceptableContentTypes(): array
+    {
+        $currentAcceptHeader = $this->headers->get('Accept');
+
+        if ($this->cachedAcceptHeader !== $currentAcceptHeader) {
+            $this->acceptableContentTypes = null;
+        }
+
+        $this->cachedAcceptHeader = $currentAcceptHeader;
+
+        return parent::getAcceptableContentTypes();
+    }
 }
diff --git a/tests/Http/HttpRequestTest.php b/tests/Http/HttpRequestTest.php
index ccf62d8e60d0..199f710ee499 100644
--- a/tests/Http/HttpRequestTest.php
+++ b/tests/Http/HttpRequestTest.php
@@ -1425,6 +1425,79 @@ public function testFormatReturnsAcceptsCharset()
         $this->assertTrue($request->accepts('application/baz+json'));
     }
 
+    public function testWantsJsonRespectsHeaderChanges()
+    {
+        $request = Request::create('/', 'GET', [], [], [], ['HTTP_ACCEPT' => '*/*']);
+        
+        $this->assertFalse($request->wantsJson());
+        
+        $this->assertTrue($request->acceptsAnyContentType());
+        
+        $request->headers->set('Accept', 'application/json');
+
+        $this->assertTrue($request->wantsJson(), 'wantsJson() should return true after Accept header is changed to application/json');
+    }
+
+    public function testAcceptsJsonRespectsHeaderChanges()
+    {
+        $request = Request::create('/', 'GET', [], [], [], ['HTTP_ACCEPT' => '*/*']);
+
+        $this->assertTrue($request->acceptsAnyContentType());
+
+        $request->headers->set('Accept', 'application/json');
+
+        $this->assertTrue($request->acceptsJson(), 'acceptsJson() should return true after Accept header is changed to application/json');
+    }
+
+    public function testPrefersRespectsHeaderChanges()
+    {
+        $request = Request::create('/', 'GET', [], [], [], ['HTTP_ACCEPT' => '*/*']);
+        
+        $this->assertTrue($request->acceptsAnyContentType());
+        
+        $request->headers->set('Accept', 'application/json');
+        
+        $this->assertSame('json', $request->prefers(['html', 'json']), 'prefers() should return json after Accept header is changed to application/json');
+    }
+
+    public function testWantsJsonWorksWhenHeaderSetBeforeFirstCall()
+    {
+        $request = Request::create('/', 'GET', [], [], [], []);
+        
+        $request->headers->set('Accept', 'application/json');
+        
+        $this->assertTrue($request->wantsJson(), 'wantsJson() should return true when Accept header is set to application/json');
+    }
+
+    public function testCacheClearedWhenTransitioningFromUnsetToSetHeader()
+    {
+        $request = Request::create('/', 'GET', [], [], [], []);
+        
+        $request->getAcceptableContentTypes();
+        
+        $request->headers->set('Accept', 'application/json');
+        
+        $this->assertTrue($request->wantsJson(), 'wantsJson() should return true after Accept header is set from null to application/json');
+        
+        $this->assertTrue($request->acceptsJson(), 'acceptsJson() should return true after Accept header is set from null to application/json');
+    }
+
+    public function testAcceptsJsonWorksWhenHeaderChangedMultipleTimes()
+    {
+        $request = Request::create('/', 'GET', [], [], [], ['HTTP_ACCEPT' => 'text/html']);
+        
+        $this->assertFalse($request->acceptsJson());
+        
+        $request->headers->set('Accept', 'application/json');
+        $this->assertTrue($request->acceptsJson());
+        
+        $request->headers->set('Accept', 'text/html');
+        $this->assertFalse($request->acceptsJson());
+        
+        $request->headers->set('Accept', 'application/json');
+        $this->assertTrue($request->acceptsJson());
+    }
+
     public function testBadAcceptHeader()
     {
         $request = Request::create('/', 'GET', [], [], [], ['HTTP_ACCEPT' => 'Mozilla/5.0 (Windows; U; Windows NT 5.1; pt-PT; rv:1.9.1.2) Gecko/20090729 Firefox/3.5.2 (.NET CLR 3.5.30729)']);