diff --git a/src/Framework/MockObject/Generator.php b/src/Framework/MockObject/Generator.php
index 362a0f8fa5d..394d5eaf279 100644
--- a/src/Framework/MockObject/Generator.php
+++ b/src/Framework/MockObject/Generator.php
@@ -974,7 +974,7 @@ private function generateMockClassDeclaration(array $mockClassName, bool $isInte
 
     private function canMockMethod(\ReflectionMethod $method): bool
     {
-        return !($method->isConstructor() || $method->isFinal() || $method->isPrivate() || $this->isMethodNameBlacklisted($method->getName()));
+        return !($this->isConstructor($method) || $method->isFinal() || $method->isPrivate() || $this->isMethodNameBlacklisted($method->getName()));
     }
 
     private function isMethodNameBlacklisted(string $name): bool
@@ -992,4 +992,20 @@ private function getTemplate(string $template): \Text_Template
 
         return self::$templates[$filename];
     }
+
+    /**
+     * @see https://github.com/sebastianbergmann/phpunit/issues/4139#issuecomment-605409765
+     */
+    private function isConstructor(\ReflectionMethod $method): bool
+    {
+        $methodName = \strtolower($method->getName());
+
+        if ($methodName === '__construct') {
+            return true;
+        }
+
+        $className  = \strtolower($method->getDeclaringClass()->getName());
+
+        return $methodName === $className;
+    }
 }