diff --git a/src/Framework/MockObject/Generator/Exception/CannotUseAddMethodsException.php b/src/Framework/MockObject/Generator/Exception/CannotUseAddMethodsException.php
deleted file mode 100644
index db8abd1eaa2..00000000000
--- a/src/Framework/MockObject/Generator/Exception/CannotUseAddMethodsException.php
+++ /dev/null
@@ -1,29 +0,0 @@
-<?php declare(strict_types=1);
-/*
- * This file is part of PHPUnit.
- *
- * (c) Sebastian Bergmann <sebastian@phpunit.de>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-namespace PHPUnit\Framework\MockObject\Generator;
-
-use function sprintf;
-
-/**
- * @internal This class is not covered by the backward compatibility promise for PHPUnit
- */
-final class CannotUseAddMethodsException extends \PHPUnit\Framework\Exception implements Exception
-{
-    public function __construct(string $type, string $methodName)
-    {
-        parent::__construct(
-            sprintf(
-                'Trying to configure method "%s" with addMethods(), but it exists in class "%s". Use onlyMethods() for methods that exist in the class',
-                $methodName,
-                $type,
-            ),
-        );
-    }
-}
diff --git a/src/Framework/MockObject/MockBuilder.php b/src/Framework/MockObject/MockBuilder.php
index 101a23d04be..5512ba561ec 100644
--- a/src/Framework/MockObject/MockBuilder.php
+++ b/src/Framework/MockObject/MockBuilder.php
@@ -13,7 +13,6 @@
 use function assert;
 use function debug_backtrace;
 use PHPUnit\Event\Facade as EventFacade;
-use PHPUnit\Framework\Exception;
 use PHPUnit\Framework\InvalidArgumentException;
 use PHPUnit\Framework\MockObject\Generator\CannotUseAddMethodsException;
 use PHPUnit\Framework\MockObject\Generator\ClassIsEnumerationException;
@@ -158,55 +157,6 @@ public function onlyMethods(array $methods): self
         return $this;
     }
 
-    /**
-     * Specifies methods that don't exist in the class which you want to mock.
-     *
-     * @psalm-param list<non-empty-string> $methods
-     *
-     * @throws CannotUseAddMethodsException
-     * @throws ReflectionException
-     * @throws RuntimeException
-     *
-     * @return $this
-     *
-     * @deprecated https://github.com/sebastianbergmann/phpunit/issues/5320
-     */
-    public function addMethods(array $methods): self
-    {
-        EventFacade::emitter()->testTriggeredPhpunitDeprecation(
-            $this->testCase->valueObjectForEvents(),
-            'MockBuilder::addMethods() is deprecated and will be removed in PHPUnit 12 without replacement.',
-        );
-
-        if (empty($methods)) {
-            $this->emptyMethodsArray = true;
-
-            return $this;
-        }
-
-        try {
-            $reflector = new ReflectionClass($this->type);
-            // @codeCoverageIgnoreStart
-        } catch (\ReflectionException $e) {
-            throw new ReflectionException(
-                $e->getMessage(),
-                $e->getCode(),
-                $e,
-            );
-            // @codeCoverageIgnoreEnd
-        }
-
-        foreach ($methods as $method) {
-            if ($reflector->hasMethod($method)) {
-                throw new CannotUseAddMethodsException($this->type, $method);
-            }
-        }
-
-        $this->methods = array_merge($this->methods, $methods);
-
-        return $this;
-    }
-
     /**
      * Specifies the arguments for the constructor.
      *
diff --git a/tests/unit/Framework/MockObject/Creation/MockBuilderTest.php b/tests/unit/Framework/MockObject/Creation/MockBuilderTest.php
index 6e68f4a12eb..125e95ec7c7 100644
--- a/tests/unit/Framework/MockObject/Creation/MockBuilderTest.php
+++ b/tests/unit/Framework/MockObject/Creation/MockBuilderTest.php
@@ -21,19 +21,15 @@
 use PHPUnit\Framework\Attributes\IgnorePhpunitDeprecations;
 use PHPUnit\Framework\Attributes\Medium;
 use PHPUnit\Framework\Attributes\TestDox;
-use PHPUnit\Framework\MockObject\Generator\CannotUseAddMethodsException;
 use PHPUnit\Framework\MockObject\Generator\DuplicateMethodException;
 use PHPUnit\Framework\MockObject\Generator\InvalidMethodNameException;
 use PHPUnit\Framework\MockObject\Generator\NameAlreadyInUseException;
 use PHPUnit\Framework\TestCase;
-use PHPUnit\TestFixture\MockObject\AbstractClass;
 use PHPUnit\TestFixture\MockObject\ClassCallingMethodInConstructor;
 use PHPUnit\TestFixture\MockObject\ExtendableClass;
 use PHPUnit\TestFixture\MockObject\InterfaceWithReturnTypeDeclaration;
-use PHPUnit\TestFixture\MockObject\TraitWithConcreteAndAbstractMethod;
 
 #[CoversClass(MockBuilder::class)]
-#[CoversClass(CannotUseAddMethodsException::class)]
 #[CoversClass(DuplicateMethodException::class)]
 #[CoversClass(InvalidMethodNameException::class)]
 #[CoversClass(NameAlreadyInUseException::class)]
@@ -65,78 +61,6 @@ public function testCannotCreateMockObjectWithSpecifiedClassNameWhenClassWithTha
             ->getMock();
     }
 
-    #[IgnorePhpunitDeprecations]
-    #[TestDox('addMethods() can be used to configure an additional method for the mock object class when the original class does not have a method of the same name')]
-    public function testCanCreateMockObjectForExtendableClassWhileAddingMethodsToIt(): void
-    {
-        $double = $this->getMockBuilder(ExtendableClass::class)
-            ->addMethods(['additionalMethod'])
-            ->getMock();
-
-        $value = 'value';
-
-        $double->method('additionalMethod')->willReturn($value);
-
-        $this->assertSame($value, $double->additionalMethod());
-    }
-
-    #[IgnorePhpunitDeprecations]
-    #[TestDox('addMethods() cannot be used to configure an additional method for the mock object class when the original class has a method of the same name')]
-    public function testCannotCreateMockObjectForExtendableClassAddingMethodToItThatItAlreadyHas(): void
-    {
-        $this->expectException(CannotUseAddMethodsException::class);
-
-        $this->getMockBuilder(ExtendableClass::class)
-            ->addMethods(['doSomething'])
-            ->getMock();
-    }
-
-    #[IgnorePhpunitDeprecations]
-    #[TestDox('addMethods() cannot be used to configure an additional method for the mock object class multiple times using the same name')]
-    public function testCannotCreateMockObjectForExtendableClassAddingMultipleMethodsWithSameNameToIt(): void
-    {
-        $this->expectException(DuplicateMethodException::class);
-
-        $this->getMockBuilder(ExtendableClass::class)
-            ->addMethods(['additionalMethod', 'additionalMethod'])
-            ->getMock();
-    }
-
-    #[IgnorePhpunitDeprecations]
-    #[TestDox('addMethods() cannot be used to configure an additional method for the mock object class with invalid name')]
-    public function testCannotCreateMockObjectForExtendableClassAddingMethodToItWithInvalidName(): void
-    {
-        $this->expectException(InvalidMethodNameException::class);
-
-        $this->getMockBuilder(ExtendableClass::class)
-            ->addMethods(['1234'])
-            ->getMock();
-    }
-
-    #[IgnorePhpunitDeprecations]
-    #[TestDox('getMockForAbstractClass() can be used to create a mock object for an abstract class')]
-    public function testCreatesMockObjectForAbstractClassAndAllowsConfigurationOfAbstractMethods(): void
-    {
-        $double = $this->getMockBuilder(AbstractClass::class)
-            ->getMockForAbstractClass();
-
-        $double->expects($this->once())->method('doSomethingElse')->willReturn(true);
-
-        $this->assertTrue($double->doSomething());
-    }
-
-    #[IgnorePhpunitDeprecations]
-    #[TestDox('getMockForTrait() can be used to create a mock object for a trait')]
-    public function testCreatesMockObjectForTraitAndAllowsConfigurationOfMethods(): void
-    {
-        $double = $this->getMockBuilder(TraitWithConcreteAndAbstractMethod::class)
-            ->getMockForTrait();
-
-        $double->method('abstractMethod')->willReturn(true);
-
-        $this->assertTrue($double->concreteMethod());
-    }
-
     #[IgnorePhpunitDeprecations]
     #[TestDox('onlyMethods() can be used to configure which methods should be doubled')]
     public function testCreatesPartialMockObjectForExtendableClass(): void