diff --git a/config/services.xml b/config/services.xml
index 5dc8457f6..6232ad049 100644
--- a/config/services.xml
+++ b/config/services.xml
@@ -169,6 +169,10 @@
             <tag name="nelmio_api_doc.schema_describer" priority="100" />
         </service>
 
+        <service id="nelmio_api_doc.schema_describer.array" class="Nelmio\ApiDocBundle\TypeDescriber\ArrayDescriber" public="false">
+            <tag name="nelmio_api_doc.schema_describer" />
+        </service>
+
         <service id="nelmio_api_doc.schema_describer.bool" class="Nelmio\ApiDocBundle\TypeDescriber\BoolDescriber" public="false">
             <tag name="nelmio_api_doc.schema_describer" />
         </service>
diff --git a/src/TypeDescriber/ArrayDescriber.php b/src/TypeDescriber/ArrayDescriber.php
new file mode 100644
index 000000000..1eb6e8245
--- /dev/null
+++ b/src/TypeDescriber/ArrayDescriber.php
@@ -0,0 +1,61 @@
+<?php
+
+/*
+ * This file is part of the NelmioApiDocBundle package.
+ *
+ * (c) Nelmio
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Nelmio\ApiDocBundle\TypeDescriber;
+
+use OpenApi\Annotations\Schema;
+use Symfony\Component\TypeInfo\Type;
+use Symfony\Component\TypeInfo\Type\CollectionType;
+use Symfony\Component\TypeInfo\TypeFactoryTrait;
+
+/**
+ * @implements TypeDescriberInterface<CollectionType>
+ *
+ * @experimental
+ *
+ * @internal
+ */
+final class ArrayDescriber implements TypeDescriberInterface, TypeDescriberAwareInterface
+{
+    use TypeDescriberAwareTrait;
+
+    public function describe(Type $type, Schema $schema, array $context = []): void
+    {
+        if (!$type->getCollectionKeyType() instanceof Type\CompositeTypeInterface) {
+            return;
+        }
+
+        $collections = array_map(
+            fn (Type $keyType): CollectionType => TypeFactoryTrait::collection($type->getWrappedType(), $type->getCollectionValueType(), $keyType),
+            $type->getCollectionKeyType()->getTypes(),
+        );
+
+        if ($type->getCollectionKeyType() instanceof Type\UnionType) {
+            $describeType = Type::union(...$collections);
+        }
+
+        if ($type->getCollectionKeyType() instanceof Type\IntersectionType) {
+            $describeType = Type::intersection(...$collections);
+        }
+
+        if (!isset($describeType)) {
+            return;
+        }
+
+        $this->describer->describe($describeType, $schema, $context);
+    }
+
+    public function supports(Type $type, array $context = []): bool
+    {
+        return $type instanceof CollectionType
+            && $type->getCollectionKeyType() instanceof Type\CompositeTypeInterface;
+    }
+}
diff --git a/src/TypeDescriber/DictionaryDescriber.php b/src/TypeDescriber/DictionaryDescriber.php
index 5d6c5de9e..cc63ed06c 100644
--- a/src/TypeDescriber/DictionaryDescriber.php
+++ b/src/TypeDescriber/DictionaryDescriber.php
@@ -40,6 +40,7 @@ public function describe(Type $type, Schema $schema, array $context = []): void
     public function supports(Type $type, array $context = []): bool
     {
         return $type instanceof CollectionType
+            && false === $type->getCollectionKeyType() instanceof Type\UnionType
             && $type->getCollectionKeyType()->isIdentifiedBy(TypeIdentifier::STRING);
     }
 }
diff --git a/src/TypeDescriber/ListDescriber.php b/src/TypeDescriber/ListDescriber.php
index d697e6982..74a94fb7e 100644
--- a/src/TypeDescriber/ListDescriber.php
+++ b/src/TypeDescriber/ListDescriber.php
@@ -40,6 +40,7 @@ public function describe(Type $type, Schema $schema, array $context = []): void
     public function supports(Type $type, array $context = []): bool
     {
         return $type instanceof CollectionType
+            && false === $type->getCollectionKeyType() instanceof Type\UnionType
             && $type->getCollectionKeyType()->isIdentifiedBy(TypeIdentifier::INT);
     }
 }