diff --git a/ChangeLog-10.0.md b/ChangeLog-10.0.md
index 2842c46db07..5b719399a06 100644
--- a/ChangeLog-10.0.md
+++ b/ChangeLog-10.0.md
@@ -7,6 +7,7 @@ All notable changes of the PHPUnit 10.0 release series are documented in this fi
 ### Removed
 
 * [#4063](https://github.com/sebastianbergmann/phpunit/issues/4063): Remove `assertNotIsReadable()`
+* [#4066](https://github.com/sebastianbergmann/phpunit/issues/4066): Remove `assertNotIsWritable()`
 * [#4142](https://github.com/sebastianbergmann/phpunit/issues/4142): Remove Prophecy integration
 
 [10.0.0]: https://github.com/sebastianbergmann/phpunit/compare/9.5...master
diff --git a/src/Framework/Assert.php b/src/Framework/Assert.php
index 8c777eebe8b..d14da88cda8 100644
--- a/src/Framework/Assert.php
+++ b/src/Framework/Assert.php
@@ -771,23 +771,6 @@ public static function assertIsNotWritable(string $filename, string $message = '
         static::assertThat($filename, new LogicalNot(new IsWritable), $message);
     }
 
-    /**
-     * Asserts that a file/dir exists and is not writable.
-     *
-     * @throws ExpectationFailedException
-     * @throws \SebastianBergmann\RecursionContext\InvalidArgumentException
-     *
-     * @codeCoverageIgnore
-     *
-     * @deprecated https://github.com/sebastianbergmann/phpunit/issues/4065
-     */
-    public static function assertNotIsWritable(string $filename, string $message = ''): void
-    {
-        self::createWarning('assertNotIsWritable() is deprecated and will be removed in PHPUnit 10. Refactor your code to use assertIsNotWritable() instead.');
-
-        static::assertThat($filename, new LogicalNot(new IsWritable), $message);
-    }
-
     /**
      * Asserts that a directory exists.
      *
diff --git a/src/Framework/Assert/Functions.php b/src/Framework/Assert/Functions.php
index 7767d685d3b..9f90a4cc746 100644
--- a/src/Framework/Assert/Functions.php
+++ b/src/Framework/Assert/Functions.php
@@ -794,27 +794,6 @@ function assertIsNotWritable(string $filename, string $message = ''): void
     }
 }
 
-if (!function_exists('PHPUnit\Framework\assertNotIsWritable')) {
-    /**
-     * Asserts that a file/dir exists and is not writable.
-     *
-     * @throws ExpectationFailedException
-     * @throws \SebastianBergmann\RecursionContext\InvalidArgumentException
-     *
-     * @codeCoverageIgnore
-     *
-     * @deprecated https://github.com/sebastianbergmann/phpunit/issues/4065
-     *
-     * @no-named-arguments Parameter names are not covered by the backward compatibility promise for PHPUnit
-     *
-     * @see Assert::assertNotIsWritable
-     */
-    function assertNotIsWritable(string $filename, string $message = ''): void
-    {
-        Assert::assertNotIsWritable(...func_get_args());
-    }
-}
-
 if (!function_exists('PHPUnit\Framework\assertDirectoryExists')) {
     /**
      * Asserts that a directory exists.