diff --git a/src/Metadata/Parameters.php b/src/Metadata/Parameters.php
index 2f20937cb64..0bb13dabf70 100644
--- a/src/Metadata/Parameters.php
+++ b/src/Metadata/Parameters.php
@@ -37,9 +37,13 @@ public function __construct(array $parameters = [])
                 $parameterName = $parameter->getKey();
             }
 
-            $this->parameters[] = [$parameterName, $parameter];
+            $key = \sprintf('%s.%s', $parameter::class, $parameterName);
+
+            $this->parameters[$key] = [$parameterName, $parameter];
         }
 
+        $this->parameters = array_values($this->parameters);
+
         $this->sort();
     }
 
diff --git a/src/Metadata/Tests/ParametersTest.php b/src/Metadata/Tests/ParametersTest.php
index 6b7b5583390..edc26ff817a 100644
--- a/src/Metadata/Tests/ParametersTest.php
+++ b/src/Metadata/Tests/ParametersTest.php
@@ -13,6 +13,7 @@
 
 namespace ApiPlatform\Metadata\Tests;
 
+use ApiPlatform\Metadata\HeaderParameter;
 use ApiPlatform\Metadata\Parameters;
 use ApiPlatform\Metadata\QueryParameter;
 use PHPUnit\Framework\TestCase;
@@ -25,4 +26,27 @@ public function testDefaultValue(): void
         $parameters = new Parameters(['a' => $r]);
         $this->assertSame($r, $parameters->get('a'));
     }
+
+    public function testDuplicated(): void
+    {
+        $r1 = new QueryParameter(key: 'a');
+        $r2 = new QueryParameter(key: 'b');
+        $r3 = new HeaderParameter(key: 'a');
+        $r4 = new HeaderParameter(key: 'b');
+        $parameters = new Parameters([$r1, $r2, $r3, $r4]);
+        $this->assertCount(4, $parameters);
+        $this->assertSame($r1, $parameters->get('a'));
+        $this->assertSame($r2, $parameters->get('b'));
+        $this->assertSame($r3, $parameters->get('a', HeaderParameter::class));
+        $this->assertSame($r4, $parameters->get('b', HeaderParameter::class));
+
+        $r1 = new QueryParameter(key: 'a');
+        $r2 = new QueryParameter(key: 'a');
+        $r3 = new HeaderParameter(key: 'a');
+        $r4 = new HeaderParameter(key: 'a');
+        $parameters = new Parameters([$r1, $r2, $r3, $r4]);
+        $this->assertCount(2, $parameters);
+        $this->assertSame($r2, $parameters->get('a'));
+        $this->assertSame($r4, $parameters->get('a', HeaderParameter::class));
+    }
 }