diff --git a/src/JsonSchema/DefinitionNameFactory.php b/src/JsonSchema/DefinitionNameFactory.php
index 86076def71c..9cfbb7deb07 100644
--- a/src/JsonSchema/DefinitionNameFactory.php
+++ b/src/JsonSchema/DefinitionNameFactory.php
@@ -21,6 +21,9 @@ final class DefinitionNameFactory implements DefinitionNameFactoryInterface
 {
     use ResourceClassInfoTrait;
 
+    private const GLUE = '.';
+    private array $prefixCache = [];
+
     public function __construct(private ?array $distinctFormats)
     {
     }
@@ -32,18 +35,18 @@ public function create(string $className, string $format = 'json', ?string $inpu
         }
 
         if (!isset($prefix)) {
-            $prefix = (new \ReflectionClass($className))->getShortName();
+            $prefix = $this->createPrefixFromClass($className);
         }
 
         if (null !== $inputOrOutputClass && $className !== $inputOrOutputClass) {
             $parts = explode('\\', $inputOrOutputClass);
             $shortName = end($parts);
-            $prefix .= '.'.$shortName;
+            $prefix .= self::GLUE.$shortName;
         }
 
         if ('json' !== $format && ($this->distinctFormats[$format] ?? false)) {
             // JSON is the default, and so isn't included in the definition name
-            $prefix .= '.'.$format;
+            $prefix .= self::GLUE.$format;
         }
 
         $definitionName = $serializerContext[SchemaFactory::OPENAPI_DEFINITION_NAME] ?? null;
@@ -61,4 +64,22 @@ private function encodeDefinitionName(string $name): string
     {
         return preg_replace('/[^a-zA-Z0-9.\-_]/', '.', $name);
     }
+
+    private function createPrefixFromClass(string $fullyQualifiedClassName, int $namespaceParts = 1): string
+    {
+        $parts = explode('\\', $fullyQualifiedClassName);
+        $name = implode(self::GLUE, \array_slice($parts, -$namespaceParts));
+
+        if (!isset($this->prefixCache[$name])) {
+            $this->prefixCache[$name] = $fullyQualifiedClassName;
+
+            return $name;
+        }
+
+        if ($this->prefixCache[$name] !== $fullyQualifiedClassName) {
+            $name = $this->createPrefixFromClass($fullyQualifiedClassName, ++$namespaceParts);
+        }
+
+        return $name;
+    }
 }
diff --git a/tests/JsonSchema/DefinitionNameFactoryTest.php b/tests/JsonSchema/DefinitionNameFactoryTest.php
index 10444160fe7..519fcfcad42 100644
--- a/tests/JsonSchema/DefinitionNameFactoryTest.php
+++ b/tests/JsonSchema/DefinitionNameFactoryTest.php
@@ -69,4 +69,29 @@ public function testCreate(string $expected, string $className, string $format =
 
         static::assertSame($expected, $definitionNameFactory->create($className, $format, $inputOrOutputClass, $operation, $serializerContext));
     }
+
+    public function testCreateDifferentPrefixesForClassesWithTheSameShortName(): void
+    {
+        $definitionNameFactory = new DefinitionNameFactory(['jsonapi' => true, 'jsonhal' => true]);
+
+        self::assertEquals(
+            'DummyClass.jsonapi',
+            $definitionNameFactory->create(\ApiPlatform\Tests\JsonSchema\Dummy\NamespaceA\Module\DummyClass::class, 'jsonapi')
+        );
+
+        self::assertEquals(
+            'Module.DummyClass.jsonapi',
+            $definitionNameFactory->create(\ApiPlatform\Tests\JsonSchema\Dummy\NamespaceB\Module\DummyClass::class, 'jsonapi')
+        );
+
+        self::assertEquals(
+            'NamespaceC.Module.DummyClass.jsonapi',
+            $definitionNameFactory->create(\ApiPlatform\Tests\JsonSchema\Dummy\NamespaceC\Module\DummyClass::class, 'jsonapi')
+        );
+
+        self::assertEquals(
+            'DummyClass.jsonhal',
+            $definitionNameFactory->create(\ApiPlatform\Tests\JsonSchema\Dummy\NamespaceA\Module\DummyClass::class, 'jsonhal')
+        );
+    }
 }
diff --git a/tests/JsonSchema/Dummy/NamespaceA/Module/DummyClass.php b/tests/JsonSchema/Dummy/NamespaceA/Module/DummyClass.php
new file mode 100644
index 00000000000..6ea133b25ef
--- /dev/null
+++ b/tests/JsonSchema/Dummy/NamespaceA/Module/DummyClass.php
@@ -0,0 +1,18 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Tests\JsonSchema\Dummy\NamespaceA\Module;
+
+class DummyClass
+{
+}
diff --git a/tests/JsonSchema/Dummy/NamespaceB/Module/DummyClass.php b/tests/JsonSchema/Dummy/NamespaceB/Module/DummyClass.php
new file mode 100644
index 00000000000..5fbe6f30d10
--- /dev/null
+++ b/tests/JsonSchema/Dummy/NamespaceB/Module/DummyClass.php
@@ -0,0 +1,18 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Tests\JsonSchema\Dummy\NamespaceB\Module;
+
+class DummyClass
+{
+}
diff --git a/tests/JsonSchema/Dummy/NamespaceC/Module/DummyClass.php b/tests/JsonSchema/Dummy/NamespaceC/Module/DummyClass.php
new file mode 100644
index 00000000000..f5b4449ac80
--- /dev/null
+++ b/tests/JsonSchema/Dummy/NamespaceC/Module/DummyClass.php
@@ -0,0 +1,18 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Tests\JsonSchema\Dummy\NamespaceC\Module;
+
+class DummyClass
+{
+}