diff --git a/modules/openapi-generator/src/main/resources/php/EnumInterface.mustache b/modules/openapi-generator/src/main/resources/php/EnumInterface.mustache
new file mode 100644
index 000000000000..b731ee93fc89
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/php/EnumInterface.mustache
@@ -0,0 +1,36 @@
+<?php
+/**
+ * EnumInterface
+ *
+ * PHP version 7.3
+ *
+ * @category Class
+ * @package  {{modelPackage}}
+ * @author   OpenAPI Generator team
+ * @link     https://openapi-generator.tech
+ */
+
+{{>partial_header}}
+/**
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+namespace {{modelPackage}};
+
+/**
+ * Interface abstracting enum access.
+ *
+ * @package {{modelPackage}}
+ * @author  OpenAPI Generator team
+ */
+interface EnumInterface
+{
+    public static function getAllowableEnumValues(): array;
+
+    /**
+     * @return mixed
+     */
+    public function getValue();
+}
diff --git a/modules/openapi-generator/src/main/resources/php/ObjectSerializer.mustache b/modules/openapi-generator/src/main/resources/php/ObjectSerializer.mustache
index 7d48d3557c34..51040326df4a 100644
--- a/modules/openapi-generator/src/main/resources/php/ObjectSerializer.mustache
+++ b/modules/openapi-generator/src/main/resources/php/ObjectSerializer.mustache
@@ -19,6 +19,7 @@
 
 namespace {{invokerPackage}};
 
+use {{modelPackage}}\EnumInterface;
 use {{modelPackage}}\ModelInterface;
 
 /**
@@ -78,9 +79,9 @@ class ObjectSerializer
                     $getter = $data::getters()[$property];
                     $value = $data->$getter();
                     if ($value !== null && !in_array($openAPIType, [{{&primitives}}], true)) {
-                        $callable = [$openAPIType, 'getAllowableEnumValues'];
-                        if (is_callable($callable)) {
-                            /** array $callable */
+                        if ($value instanceof EnumInterface) {
+                            $value = $value->getValue();
+                            $callable = [$openAPIType, 'getAllowableEnumValues'];
                             $allowedEnumTypes = $callable();
                             if (!in_array($value, $allowedEnumTypes, true)) {
                                 $imploded = implode("', '", $allowedEnumTypes);
diff --git a/modules/openapi-generator/src/main/resources/php/model_enum.mustache b/modules/openapi-generator/src/main/resources/php/model_enum.mustache
index 88036f76ffc9..82d148d68577 100644
--- a/modules/openapi-generator/src/main/resources/php/model_enum.mustache
+++ b/modules/openapi-generator/src/main/resources/php/model_enum.mustache
@@ -1,4 +1,4 @@
-class {{classname}}
+class {{classname}} implements EnumInterface
 {
     /**
      * Possible values of this enum
@@ -6,9 +6,23 @@ class {{classname}}
     {{#allowableValues}}
     {{#enumVars}}
     const {{^isString}}NUMBER_{{/isString}}{{{name}}} = {{{value}}};
-
     {{/enumVars}}
     {{/allowableValues}}
+
+
+    /**
+     * @var mixed
+     */
+    private $value;
+
+    public function __construct($value)
+    {
+        if (!in_array($value, self::getAllowableEnumValues(), true)) {
+            throw new \LogicException(sprintf('%s is not a allowed value for enum', $value));
+        }
+        $this->value = $value;
+    }
+
     /**
      * Gets allowable values of the enum
      * @return string[]
@@ -25,4 +39,13 @@ class {{classname}}
 
         ];
     }
+    
+    /**
+     * @return mixed
+     */
+    #[\ReturnTypeWillChange]
+    public function getValue()
+    {
+        return $this->value;
+    }
 }
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumClass.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumClass.php
index 8fe1b2880723..a33e48c4c010 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumClass.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumClass.php
@@ -37,17 +37,29 @@
  * @author   OpenAPI Generator team
  * @link     https://openapi-generator.tech
  */
-class EnumClass
+class EnumClass implements EnumInterface
 {
     /**
      * Possible values of this enum
      */
     const ABC = '_abc';
-
     const EFG = '-efg';
-
     const XYZ = '(xyz)';
 
+
+    /**
+     * @var mixed
+     */
+    private $value;
+
+    public function __construct($value)
+    {
+        if (!in_array($value, self::getAllowableEnumValues(), true)) {
+            throw new \LogicException(sprintf('%s is not a allowed value for enum', $value));
+        }
+        $this->value = $value;
+    }
+
     /**
      * Gets allowable values of the enum
      * @return string[]
@@ -60,6 +72,15 @@ public static function getAllowableEnumValues()
             self::XYZ
         ];
     }
+    
+    /**
+     * @return mixed
+     */
+    #[\ReturnTypeWillChange]
+    public function getValue()
+    {
+        return $this->value;
+    }
 }
 
 
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnum.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnum.php
index b1b834319a8d..0c0b2a5994ab 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnum.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnum.php
@@ -37,17 +37,29 @@
  * @author   OpenAPI Generator team
  * @link     https://openapi-generator.tech
  */
-class OuterEnum
+class OuterEnum implements EnumInterface
 {
     /**
      * Possible values of this enum
      */
     const PLACED = 'placed';
-
     const APPROVED = 'approved';
-
     const DELIVERED = 'delivered';
 
+
+    /**
+     * @var mixed
+     */
+    private $value;
+
+    public function __construct($value)
+    {
+        if (!in_array($value, self::getAllowableEnumValues(), true)) {
+            throw new \LogicException(sprintf('%s is not a allowed value for enum', $value));
+        }
+        $this->value = $value;
+    }
+
     /**
      * Gets allowable values of the enum
      * @return string[]
@@ -60,6 +72,15 @@ public static function getAllowableEnumValues()
             self::DELIVERED
         ];
     }
+    
+    /**
+     * @return mixed
+     */
+    #[\ReturnTypeWillChange]
+    public function getValue()
+    {
+        return $this->value;
+    }
 }
 
 
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnumDefaultValue.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnumDefaultValue.php
index 5d88f63550c6..97e6af3e1bce 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnumDefaultValue.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnumDefaultValue.php
@@ -37,17 +37,29 @@
  * @author   OpenAPI Generator team
  * @link     https://openapi-generator.tech
  */
-class OuterEnumDefaultValue
+class OuterEnumDefaultValue implements EnumInterface
 {
     /**
      * Possible values of this enum
      */
     const PLACED = 'placed';
-
     const APPROVED = 'approved';
-
     const DELIVERED = 'delivered';
 
+
+    /**
+     * @var mixed
+     */
+    private $value;
+
+    public function __construct($value)
+    {
+        if (!in_array($value, self::getAllowableEnumValues(), true)) {
+            throw new \LogicException(sprintf('%s is not a allowed value for enum', $value));
+        }
+        $this->value = $value;
+    }
+
     /**
      * Gets allowable values of the enum
      * @return string[]
@@ -60,6 +72,15 @@ public static function getAllowableEnumValues()
             self::DELIVERED
         ];
     }
+    
+    /**
+     * @return mixed
+     */
+    #[\ReturnTypeWillChange]
+    public function getValue()
+    {
+        return $this->value;
+    }
 }
 
 
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnumInteger.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnumInteger.php
index 5bb6ee6f26e0..8903613e680a 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnumInteger.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnumInteger.php
@@ -37,17 +37,29 @@
  * @author   OpenAPI Generator team
  * @link     https://openapi-generator.tech
  */
-class OuterEnumInteger
+class OuterEnumInteger implements EnumInterface
 {
     /**
      * Possible values of this enum
      */
     const NUMBER_0 = 0;
-
     const NUMBER_1 = 1;
-
     const NUMBER_2 = 2;
 
+
+    /**
+     * @var mixed
+     */
+    private $value;
+
+    public function __construct($value)
+    {
+        if (!in_array($value, self::getAllowableEnumValues(), true)) {
+            throw new \LogicException(sprintf('%s is not a allowed value for enum', $value));
+        }
+        $this->value = $value;
+    }
+
     /**
      * Gets allowable values of the enum
      * @return string[]
@@ -60,6 +72,15 @@ public static function getAllowableEnumValues()
             self::NUMBER_2
         ];
     }
+    
+    /**
+     * @return mixed
+     */
+    #[\ReturnTypeWillChange]
+    public function getValue()
+    {
+        return $this->value;
+    }
 }
 
 
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnumIntegerDefaultValue.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnumIntegerDefaultValue.php
index f7ae2d6b29db..ad82dd385ca4 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnumIntegerDefaultValue.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterEnumIntegerDefaultValue.php
@@ -37,17 +37,29 @@
  * @author   OpenAPI Generator team
  * @link     https://openapi-generator.tech
  */
-class OuterEnumIntegerDefaultValue
+class OuterEnumIntegerDefaultValue implements EnumInterface
 {
     /**
      * Possible values of this enum
      */
     const NUMBER_0 = 0;
-
     const NUMBER_1 = 1;
-
     const NUMBER_2 = 2;
 
+
+    /**
+     * @var mixed
+     */
+    private $value;
+
+    public function __construct($value)
+    {
+        if (!in_array($value, self::getAllowableEnumValues(), true)) {
+            throw new \LogicException(sprintf('%s is not a allowed value for enum', $value));
+        }
+        $this->value = $value;
+    }
+
     /**
      * Gets allowable values of the enum
      * @return string[]
@@ -60,6 +72,15 @@ public static function getAllowableEnumValues()
             self::NUMBER_2
         ];
     }
+    
+    /**
+     * @return mixed
+     */
+    #[\ReturnTypeWillChange]
+    public function getValue()
+    {
+        return $this->value;
+    }
 }
 
 
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/ObjectSerializer.php b/samples/client/petstore/php/OpenAPIClient-php/lib/ObjectSerializer.php
index 840e4d934149..d21ded32c011 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/ObjectSerializer.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/ObjectSerializer.php
@@ -28,6 +28,7 @@
 
 namespace OpenAPI\Client;
 
+use OpenAPI\Client\Model\EnumInterface;
 use OpenAPI\Client\Model\ModelInterface;
 
 /**
@@ -87,9 +88,9 @@ public static function sanitizeForSerialization($data, $type = null, $format = n
                     $getter = $data::getters()[$property];
                     $value = $data->$getter();
                     if ($value !== null && !in_array($openAPIType, ['\DateTime', '\SplFileObject', 'array', 'bool', 'boolean', 'byte', 'double', 'float', 'int', 'integer', 'mixed', 'number', 'object', 'string', 'void'], true)) {
-                        $callable = [$openAPIType, 'getAllowableEnumValues'];
-                        if (is_callable($callable)) {
-                            /** array $callable */
+                        if ($value instanceof EnumInterface) {
+                            $value = $value->getValue();
+                            $callable = [$openAPIType, 'getAllowableEnumValues'];
                             $allowedEnumTypes = $callable();
                             if (!in_array($value, $allowedEnumTypes, true)) {
                                 $imploded = implode("', '", $allowedEnumTypes);