diff --git a/README.md b/README.md
index bbfac0a..7c10111 100644
--- a/README.md
+++ b/README.md
@@ -212,9 +212,11 @@ Method                                             | Description
 
 ### Function Assertions
 
-Method                                      | Description
-------------------------------------------- | -----------------------------------------------------------------------------------------------------
-`throws($closure, $class, $message = '')`   | Check that a function throws a certain exception. Subclasses of the exception class will be accepted.
+Method                                    | Description
+------------------------------------------| -----------------------------------------------------------------------------------------------------
+`throws($closure, $class, $message = '')` | Check that a function throws a certain exception. Subclasses of the exception class will be accepted.
+`isStatic($closure, $message = '')`       | Check that a function is static.
+`notStatic($closure, $message = '')`    | Check that a function is not static.
 
 ### Collection Assertions
 
diff --git a/src/Assert.php b/src/Assert.php
index d585aa4..6a7e345 100644
--- a/src/Assert.php
+++ b/src/Assert.php
@@ -14,9 +14,11 @@
 namespace Webmozart\Assert;
 
 use ArrayAccess;
+use Closure;
 use Countable;
 use DateTime;
 use DateTimeImmutable;
+use ReflectionFunction;
 use ReflectionProperty;
 use Throwable;
 use Traversable;
@@ -2042,6 +2044,56 @@ public static function isMap(mixed $array, string $message = ''): array
         return $array;
     }
 
+    /**
+     * @param Closure $closure
+     *
+     * @psalm-pure
+     *
+     * @psalm-assert static Closure $closure
+     *
+     * @psalm-return static Closure
+     *
+     * @throws InvalidArgumentException
+     */
+    public static function isStatic(mixed $closure, string $message = ''): Closure
+    {
+        static::isCallable($closure, $message);
+        $reflection = new ReflectionFunction($closure);
+
+        if (!$reflection->isStatic()) {
+            static::reportInvalidArgument(
+                $message ?: 'Closure is not static.'
+            );
+        }
+
+        return $closure;
+    }
+
+    /**
+     * @param Closure $closure
+     *
+     * @psalm-pure
+     *
+     * @psalm-assert Closure $closure
+     *
+     * @psalm-return Closure
+     *
+     * @throws InvalidArgumentException
+     */
+    public static function notStatic(mixed $closure, string $message = ''): Closure
+    {
+        static::isCallable($closure, $message);
+        $reflection = new ReflectionFunction($closure);
+
+        if ($reflection->isStatic()) {
+            static::reportInvalidArgument(
+                $message ?: 'Closure is not static.'
+            );
+        }
+
+        return $closure;
+    }
+
     /**
      * @psalm-pure
      *
diff --git a/src/Mixin.php b/src/Mixin.php
index c076c4e..0780cc8 100644
--- a/src/Mixin.php
+++ b/src/Mixin.php
@@ -4955,6 +4955,130 @@ public static function allNullOrIsMap(mixed $array, string $message = ''): mixed
         return $array;
     }
 
+    /**
+     * @param Closure|null $closure
+     *
+     * @psalm-pure
+     *
+     * @psalm-assert static Closure|null $closure
+     *
+     * @return static Closure|null
+     *
+     * @throws InvalidArgumentException
+     */
+    public static function nullOrIsStatic(mixed $closure, string $message = ''): mixed
+    {
+        null === $closure || static::isStatic($closure, $message);
+
+        return $closure;
+    }
+
+    /**
+     * @param iterable<Closure> $closure
+     *
+     * @psalm-pure
+     *
+     * @psalm-assert iterable<static Closure> $closure
+     *
+     * @return iterable<static Closure>
+     *
+     * @throws InvalidArgumentException
+     */
+    public static function allIsStatic(mixed $closure, string $message = ''): mixed
+    {
+        static::isIterable($closure);
+
+        foreach ($closure as $entry) {
+            static::isStatic($entry, $message);
+        }
+
+        return $closure;
+    }
+
+    /**
+     * @param iterable<Closure|null> $closure
+     *
+     * @psalm-pure
+     *
+     * @psalm-assert iterable<static Closure|null> $closure
+     *
+     * @return iterable<static Closure|null>
+     *
+     * @throws InvalidArgumentException
+     */
+    public static function allNullOrIsStatic(mixed $closure, string $message = ''): mixed
+    {
+        static::isIterable($closure);
+
+        foreach ($closure as $entry) {
+            null === $entry || static::isStatic($entry, $message);
+        }
+
+        return $closure;
+    }
+
+    /**
+     * @param Closure|null $closure
+     *
+     * @psalm-pure
+     *
+     * @psalm-assert Closure|null $closure
+     *
+     * @return Closure|null
+     *
+     * @throws InvalidArgumentException
+     */
+    public static function nullOrNotStatic(mixed $closure, string $message = ''): mixed
+    {
+        null === $closure || static::notStatic($closure, $message);
+
+        return $closure;
+    }
+
+    /**
+     * @param iterable<Closure> $closure
+     *
+     * @psalm-pure
+     *
+     * @psalm-assert iterable<Closure> $closure
+     *
+     * @return iterable<Closure>
+     *
+     * @throws InvalidArgumentException
+     */
+    public static function allNotStatic(mixed $closure, string $message = ''): mixed
+    {
+        static::isIterable($closure);
+
+        foreach ($closure as $entry) {
+            static::notStatic($entry, $message);
+        }
+
+        return $closure;
+    }
+
+    /**
+     * @param iterable<Closure|null> $closure
+     *
+     * @psalm-pure
+     *
+     * @psalm-assert iterable<Closure|null> $closure
+     *
+     * @return iterable<Closure|null>
+     *
+     * @throws InvalidArgumentException
+     */
+    public static function allNullOrNotStatic(mixed $closure, string $message = ''): mixed
+    {
+        static::isIterable($closure);
+
+        foreach ($closure as $entry) {
+            null === $entry || static::notStatic($entry, $message);
+        }
+
+        return $closure;
+    }
+
     /**
      * @psalm-pure
      *
diff --git a/tests/AssertTest.php b/tests/AssertTest.php
index 4e801eb..7ec8c6f 100644
--- a/tests/AssertTest.php
+++ b/tests/AssertTest.php
@@ -621,6 +621,10 @@ public static function getTests(): array
             ['uniqueValues', [['qwerty', 'qwerty']], false],
             ['uniqueValues', [['asdfg', 'qwerty']], true],
             ['uniqueValues', [[123, '123']], false],
+            ['isStatic', [static function () {}], true],
+            ['isStatic', [function () {}], false],
+            ['notStatic', [static function () {}], false],
+            ['notStatic', [function () {}], true],
         ];
     }
 
diff --git a/tests/static-analysis/assert-isStatic.php b/tests/static-analysis/assert-isStatic.php
new file mode 100644
index 0000000..d24cf02
--- /dev/null
+++ b/tests/static-analysis/assert-isStatic.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Webmozart\Assert\Tests\StaticAnalysis;
+
+use Closure;
+use Webmozart\Assert\Assert;
+
+function isStatic(Closure $closure): Closure
+{
+    Assert::isStatic($closure);
+
+    return $closure;
+}
diff --git a/tests/static-analysis/assert-notStatic.php b/tests/static-analysis/assert-notStatic.php
new file mode 100644
index 0000000..033335c
--- /dev/null
+++ b/tests/static-analysis/assert-notStatic.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Webmozart\Assert\Tests\StaticAnalysis;
+
+use Closure;
+use Webmozart\Assert\Assert;
+
+function notStatic(Closure $closure): Closure
+{
+    Assert::notStatic($closure);
+
+    return $closure;
+}