diff --git a/README.md b/README.md
index 43e9e464..204c9f39 100644
--- a/README.md
+++ b/README.md
@@ -243,6 +243,7 @@ Assertion::notContains(mixed $string, string $needle);
 Assertion::notEmpty(mixed $value);
 Assertion::notEmptyKey(mixed $value, string|int $key);
 Assertion::notEq(mixed $value1, mixed $value2);
+Assertion::notFalse(mixed $value);
 Assertion::notInArray(mixed $value, array $choices);
 Assertion::notIsInstanceOf(mixed $value, string $className);
 Assertion::notNull(mixed $value);
diff --git a/bin/generate_method_docs.php b/bin/generate_method_docs.php
index 849556e7..a5a18358 100644
--- a/bin/generate_method_docs.php
+++ b/bin/generate_method_docs.php
@@ -11,6 +11,7 @@
  * obtain it through the world-wide-web, please send an email
  * to kontakt@beberlei.de so I can send you a copy immediately.
  */
+
 require_once __DIR__.'/../vendor/autoload.php';
 require_once __DIR__.'/MethodDocGenerator.php';
 
diff --git a/lib/Assert/Assertion.php b/lib/Assert/Assertion.php
index 2e493a62..5a48344f 100644
--- a/lib/Assert/Assertion.php
+++ b/lib/Assert/Assertion.php
@@ -83,6 +83,7 @@
  * @method static bool allNotEmpty(mixed $value, string|callable $message = null, string $propertyPath = null) Assert that value is not empty for all values.
  * @method static bool allNotEmptyKey(mixed $value, string|int $key, string|callable $message = null, string $propertyPath = null) Assert that key exists in an array/array-accessible object and its value is not empty for all values.
  * @method static bool allNotEq(mixed $value1, mixed $value2, string|callable $message = null, string $propertyPath = null) Assert that two values are not equal (using == ) for all values.
+ * @method static bool allNotFalse(mixed $value, string|callable $message = null, string $propertyPath = null) Assert that value is not false for all values.
  * @method static bool allNotInArray(mixed $value, array $choices, string|callable $message = null, string $propertyPath = null) Assert that value is not in array of choices for all values.
  * @method static bool allNotIsInstanceOf(mixed $value, string $className, string|callable $message = null, string $propertyPath = null) Assert that value is not instance of given class-name for all values.
  * @method static bool allNotNull(mixed $value, string|callable $message = null, string $propertyPath = null) Assert that value is not null for all values.
@@ -170,6 +171,7 @@
  * @method static bool nullOrNotEmpty(mixed $value, string|callable $message = null, string $propertyPath = null) Assert that value is not empty or that the value is null.
  * @method static bool nullOrNotEmptyKey(mixed $value, string|int $key, string|callable $message = null, string $propertyPath = null) Assert that key exists in an array/array-accessible object and its value is not empty or that the value is null.
  * @method static bool nullOrNotEq(mixed $value1, mixed $value2, string|callable $message = null, string $propertyPath = null) Assert that two values are not equal (using == ) or that the value is null.
+ * @method static bool nullOrNotFalse(mixed $value, string|callable $message = null, string $propertyPath = null) Assert that value is not false or that the value is null.
  * @method static bool nullOrNotInArray(mixed $value, array $choices, string|callable $message = null, string $propertyPath = null) Assert that value is not in array of choices or that the value is null.
  * @method static bool nullOrNotIsInstanceOf(mixed $value, string $className, string|callable $message = null, string $propertyPath = null) Assert that value is not instance of given class-name or that the value is null.
  * @method static bool nullOrNotNull(mixed $value, string|callable $message = null, string $propertyPath = null) Assert that value is not null or that the value is null.
@@ -276,6 +278,7 @@ class Assertion
     const INVALID_MIN_COUNT = 227;
     const INVALID_MAX_COUNT = 228;
     const INVALID_STRING_NOT_CONTAINS = 229;
+    const INVALID_NOT_FALSE = 230;
 
     /**
      * Exception to throw when an assertion failed.
@@ -649,6 +652,29 @@ public static function notNull($value, $message = null, $propertyPath = null)
         return true;
     }
 
+    /**
+     * Assert that value is not false.
+     *
+     * @param mixed                $value
+     * @param string|callable|null $message
+     * @param string|null          $propertyPath
+     *
+     * @return bool
+     */
+    public static function notFalse($value, $message = null, $propertyPath = null)
+    {
+        if (false === $value) {
+            $message = \sprintf(
+                static::generateMessage($message ?: 'Value "%s" is false, but non false value was expected.'),
+                static::stringify($value)
+            );
+
+            throw static::createException($value, $message, static::INVALID_NOT_FALSE, $propertyPath);
+        }
+
+        return true;
+    }
+
     /**
      * Assert that value is a string.
      *
@@ -2428,7 +2454,7 @@ public static function satisfy($value, $callback, $message = null, $propertyPath
      * (using input_filter/FILTER_VALIDATE_IP).
      *
      * @param string               $value
-     * @param null|int             $flag
+     * @param int|null             $flag
      * @param string|callable|null $message
      * @param string|null          $propertyPath
      *
@@ -2455,7 +2481,7 @@ public static function ip($value, $flag = null, $message = null, $propertyPath =
      * (using input_filter/FILTER_VALIDATE_IP).
      *
      * @param string               $value
-     * @param null|int             $flag
+     * @param int|null             $flag
      * @param string|callable|null $message
      * @param string|null          $propertyPath
      *
@@ -2475,7 +2501,7 @@ public static function ipv4($value, $flag = null, $message = null, $propertyPath
      * (using input_filter/FILTER_VALIDATE_IP).
      *
      * @param string               $value
-     * @param null|int             $flag
+     * @param int|null             $flag
      * @param string|callable|null $message
      * @param string|null          $propertyPath
      *
diff --git a/lib/Assert/AssertionChain.php b/lib/Assert/AssertionChain.php
index 5d48377a..eae54132 100644
--- a/lib/Assert/AssertionChain.php
+++ b/lib/Assert/AssertionChain.php
@@ -84,6 +84,7 @@
  * @method AssertionChain notEmpty(string|callable $message = null, string $propertyPath = null) Assert that value is not empty.
  * @method AssertionChain notEmptyKey(string|int $key, string|callable $message = null, string $propertyPath = null) Assert that key exists in an array/array-accessible object and its value is not empty.
  * @method AssertionChain notEq(mixed $value2, string|callable $message = null, string $propertyPath = null) Assert that two values are not equal (using == ).
+ * @method AssertionChain notFalse(string|callable $message = null, string $propertyPath = null) Assert that value is not false.
  * @method AssertionChain notInArray(array $choices, string|callable $message = null, string $propertyPath = null) Assert that value is not in array of choices.
  * @method AssertionChain notIsInstanceOf(string $className, string|callable $message = null, string $propertyPath = null) Assert that value is not instance of given class-name.
  * @method AssertionChain notNull(string|callable $message = null, string $propertyPath = null) Assert that value is not null.
diff --git a/lib/Assert/LazyAssertion.php b/lib/Assert/LazyAssertion.php
index 0d780750..e2b272d0 100644
--- a/lib/Assert/LazyAssertion.php
+++ b/lib/Assert/LazyAssertion.php
@@ -83,6 +83,7 @@
  * @method LazyAssertion notEmpty(string|callable $message = null, string $propertyPath = null) Assert that value is not empty.
  * @method LazyAssertion notEmptyKey(string|int $key, string|callable $message = null, string $propertyPath = null) Assert that key exists in an array/array-accessible object and its value is not empty.
  * @method LazyAssertion notEq(mixed $value2, string|callable $message = null, string $propertyPath = null) Assert that two values are not equal (using == ).
+ * @method LazyAssertion notFalse(string|callable $message = null, string $propertyPath = null) Assert that value is not false.
  * @method LazyAssertion notInArray(array $choices, string|callable $message = null, string $propertyPath = null) Assert that value is not in array of choices.
  * @method LazyAssertion notIsInstanceOf(string $className, string|callable $message = null, string $propertyPath = null) Assert that value is not instance of given class-name.
  * @method LazyAssertion notNull(string|callable $message = null, string $propertyPath = null) Assert that value is not null.
diff --git a/tests/Assert/Tests/AssertTest.php b/tests/Assert/Tests/AssertTest.php
index 5fa07302..dbd97d3f 100644
--- a/tests/Assert/Tests/AssertTest.php
+++ b/tests/Assert/Tests/AssertTest.php
@@ -300,6 +300,25 @@ public function testInvalidNotNull()
         Assertion::notNull(null);
     }
 
+    public function testNotFalse()
+    {
+        $this->assertTrue(Assertion::notFalse('1'));
+        $this->assertTrue(Assertion::notFalse(1));
+        $this->assertTrue(Assertion::notFalse(0));
+        $this->assertTrue(Assertion::notFalse([]));
+        $this->assertTrue(Assertion::notFalse(true));
+        $this->assertTrue(Assertion::notFalse(null));
+    }
+
+    /**
+     * @expectedException \Assert\AssertionFailedException
+     * @expectedExceptionCode \Assert\Assertion::INVALID_NOT_FALSE
+     */
+    public function testInvalidNotFalse()
+    {
+        Assertion::notFalse(false);
+    }
+
     public function testString()
     {
         $this->assertTrue(Assertion::string('test-string'));
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index ae659cf5..3c231132 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -11,6 +11,7 @@
  * obtain it through the world-wide-web, please send an email
  * to kontakt@beberlei.de so I can send you a copy immediately.
  */
+
 $loader = @include __DIR__.'/../vendor/autoload.php';
 if (!$loader) {
     die(<<<'EOT'