diff --git a/docs/03-rules.md b/docs/03-rules.md
index a435d51..7d5bd3b 100644
--- a/docs/03-rules.md
+++ b/docs/03-rules.md
@@ -14,6 +14,7 @@
 - [Count](03-rules_count.md)
 - [IsNull](03-rules_is-null.md)
 - [NotBlank](03-rules_not-blank.md)
+- [NotNull](03-rules_not-null.md)
 - [Type](03-rules_type.md)
 
 ## String Rules
diff --git a/docs/03-rules_is-null.md b/docs/03-rules_is-null.md
index 00afcf9..0325250 100644
--- a/docs/03-rules_is-null.md
+++ b/docs/03-rules_is-null.md
@@ -2,6 +2,8 @@
 
 Validates that a value is `null`.
 
+Check the [NotNull](03-rules_not-null.md) rule for the opposite validation.
+
 ```php
 IsNull(
     ?string $message = null
diff --git a/docs/03-rules_not-null.md b/docs/03-rules_not-null.md
new file mode 100644
index 0000000..b249142
--- /dev/null
+++ b/docs/03-rules_not-null.md
@@ -0,0 +1,36 @@
+# NotNull
+
+Validates that a value is not `null`.
+
+Check the [IsNull](03-rules_is-null.md) rule for the opposite validation.
+
+```php
+NotNull(
+    ?string $message = null
+);
+```
+
+## Basic Usage
+
+```php
+// anything else will be true
+Validator::notNull()->validate(null); // false
+```
+
+## Options
+
+### `message`
+
+type: `?string` default: `The {{ name }} value should not be null.`
+
+Message that will be shown if the value is not null.
+
+The following parameters are available:
+
+| Parameter     | Description               |
+|---------------|---------------------------|
+| `{{ name }}`  | Name of the invalid value |
+
+## Changelog
+
+- `1.3.0` Created
\ No newline at end of file
diff --git a/src/ChainedValidatorInterface.php b/src/ChainedValidatorInterface.php
index 8aec8f0..035cf9b 100644
--- a/src/ChainedValidatorInterface.php
+++ b/src/ChainedValidatorInterface.php
@@ -121,6 +121,10 @@ public function notBlank(
         ?string $message = null
     ): ChainedValidatorInterface&Validator;
 
+    public function notNull(
+        ?string $message = null
+    ): ChainedValidatorInterface&Validator;
+
     public function optional(
         Validator $validator
     ): ChainedValidatorInterface&Validator;
diff --git a/src/Exception/NotNullException.php b/src/Exception/NotNullException.php
new file mode 100644
index 0000000..8dded16
--- /dev/null
+++ b/src/Exception/NotNullException.php
@@ -0,0 +1,5 @@
+<?php
+
+namespace ProgrammatorDev\Validator\Exception;
+
+class NotNullException extends ValidationException {}
\ No newline at end of file
diff --git a/src/Rule/NotNull.php b/src/Rule/NotNull.php
new file mode 100644
index 0000000..e3e625e
--- /dev/null
+++ b/src/Rule/NotNull.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace ProgrammatorDev\Validator\Rule;
+
+use ProgrammatorDev\Validator\Exception\NotNullException;
+use ProgrammatorDev\Validator\Validator;
+
+class NotNull extends AbstractRule implements RuleInterface
+{
+    private string $message = 'The {{ name }} value should not be null.';
+
+    public function __construct(
+        ?string $message = null
+    )
+    {
+        $this->message = $message ?? $this->message;
+    }
+
+    public function assert(mixed $value, ?string $name = null): void
+    {
+        if (Validator::isNull()->validate($value) === true) {
+            throw new NotNullException(
+                message: $this->message,
+                parameters: [
+                    'name' => $name
+                ]
+            );
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/StaticValidatorInterface.php b/src/StaticValidatorInterface.php
index 7b759c8..f72dc2b 100644
--- a/src/StaticValidatorInterface.php
+++ b/src/StaticValidatorInterface.php
@@ -120,6 +120,10 @@ public static function notBlank(
         ?string $message = null
     ): ChainedValidatorInterface&Validator;
 
+    public static function notNull(
+        ?string $message = null
+    ): ChainedValidatorInterface&Validator;
+
     public static function optional(
         Validator $validator
     ): ChainedValidatorInterface&Validator;
diff --git a/tests/NotNullTest.php b/tests/NotNullTest.php
new file mode 100644
index 0000000..c73d9b7
--- /dev/null
+++ b/tests/NotNullTest.php
@@ -0,0 +1,43 @@
+<?php
+
+namespace ProgrammatorDev\Validator\Test;
+
+use ProgrammatorDev\Validator\Exception\NotNullException;
+use ProgrammatorDev\Validator\Rule\NotNull;
+use ProgrammatorDev\Validator\Test\Util\TestRuleFailureConditionTrait;
+use ProgrammatorDev\Validator\Test\Util\TestRuleMessageOptionTrait;
+use ProgrammatorDev\Validator\Test\Util\TestRuleSuccessConditionTrait;
+
+class NotNullTest extends AbstractTest
+{
+    use TestRuleFailureConditionTrait;
+    use TestRuleSuccessConditionTrait;
+    use TestRuleMessageOptionTrait;
+
+    public static function provideRuleFailureConditionData(): \Generator
+    {
+        $exception = NotNullException::class;
+        $message = '/The (.*) value should not be null\./';
+
+        yield 'null' => [new NotNull(), null, $exception, $message];
+    }
+
+    public static function provideRuleSuccessConditionData(): \Generator
+    {
+        yield 'int' => [new NotNull(), 1];
+        yield 'string' => [new NotNull(), 'string'];
+        yield 'bool' => [new NotNull(), true];
+        yield 'array' => [new NotNull(), []];
+    }
+
+    public static function provideRuleMessageOptionData(): \Generator
+    {
+        yield 'message' => [
+            new NotNull(
+                message: '{{ name }}'
+            ),
+            null,
+            'test'
+        ];
+    }
+}
\ No newline at end of file