diff --git a/composer.json b/composer.json
index f2d4f0b..015ff0c 100644
--- a/composer.json
+++ b/composer.json
@@ -20,7 +20,8 @@
         "illuminate/console": "^10.0|^11.0",
         "illuminate/support": "^10.0|^11.0",
         "spatie/laravel-package-tools": "^1.16.2",
-        "symfony/polyfill-php83": "^1.30"
+        "symfony/polyfill-php83": "^1.30",
+        "webmozart/assert": "^1.11"
     },
     "require-dev": {
         "illuminate/testing": "^10.0|^11.0",
diff --git a/src/AndSpecification.php b/src/AndSpecification.php
index e37068d..842c60d 100644
--- a/src/AndSpecification.php
+++ b/src/AndSpecification.php
@@ -5,6 +5,7 @@
 namespace Maartenpaauw\Specifications;
 
 use Override;
+use Webmozart\Assert\Assert;
 
 /**
  * @template TCandidate
@@ -18,7 +19,9 @@ final class AndSpecification extends CompositeSpecification
      */
     public function __construct(
         private readonly array $specifications,
-    ) {}
+    ) {
+        Assert::allIsInstanceOf($specifications, Specification::class);
+    }
 
     #[Override]
     public function isSatisfiedBy(mixed $candidate): bool
diff --git a/src/OrSpecification.php b/src/OrSpecification.php
index aa4d2f1..ab8c8d5 100644
--- a/src/OrSpecification.php
+++ b/src/OrSpecification.php
@@ -5,6 +5,7 @@
 namespace Maartenpaauw\Specifications;
 
 use Override;
+use Webmozart\Assert\Assert;
 
 /**
  * @template TCandidate
@@ -18,7 +19,9 @@ final class OrSpecification extends CompositeSpecification
      */
     public function __construct(
         private readonly array $specifications,
-    ) {}
+    ) {
+        Assert::allIsInstanceOf($this->specifications, Specification::class);
+    }
 
     #[Override]
     public function isSatisfiedBy(mixed $candidate): bool
diff --git a/src/XorSpecification.php b/src/XorSpecification.php
index 596da9f..a4ce277 100644
--- a/src/XorSpecification.php
+++ b/src/XorSpecification.php
@@ -5,6 +5,7 @@
 namespace Maartenpaauw\Specifications;
 
 use Override;
+use Webmozart\Assert\Assert;
 
 /**
  * @template TCandidate
@@ -18,7 +19,9 @@ final class XorSpecification extends CompositeSpecification
      */
     public function __construct(
         private readonly array $specifications,
-    ) {}
+    ) {
+        Assert::allIsInstanceOf($specifications, Specification::class);
+    }
 
     #[Override]
     public function isSatisfiedBy(mixed $candidate): bool
diff --git a/tests/AndSpecificationTest.php b/tests/AndSpecificationTest.php
index 4e2383f..8ba9a33 100644
--- a/tests/AndSpecificationTest.php
+++ b/tests/AndSpecificationTest.php
@@ -4,6 +4,7 @@
 
 namespace Maartenpaauw\Specifications\Tests;
 
+use InvalidArgumentException;
 use Maartenpaauw\Specifications\AndSpecification;
 use Workbench\App\LengthSpecification;
 use Workbench\App\UppercaseSpecification;
@@ -30,6 +31,14 @@ protected function setUp(): void
         ]);
     }
 
+    public function test_it_should_throw_an_invalid_argument_exception_when_the_specification_array_does_contain_invalid_data(): void
+    {
+        self::expectException(InvalidArgumentException::class);
+
+        // @phpstan-ignore-next-line
+        new AndSpecification(['invalid']);
+    }
+
     public function test_it_should_return_true_when_the_candidate_matches_all_specifications(): void
     {
         // Act
diff --git a/tests/OrSpecificationTest.php b/tests/OrSpecificationTest.php
index 5269296..a3b1af1 100644
--- a/tests/OrSpecificationTest.php
+++ b/tests/OrSpecificationTest.php
@@ -4,6 +4,7 @@
 
 namespace Maartenpaauw\Specifications\Tests;
 
+use InvalidArgumentException;
 use Maartenpaauw\Specifications\OrSpecification;
 use Workbench\App\LengthSpecification;
 use Workbench\App\UppercaseSpecification;
@@ -30,6 +31,14 @@ protected function setUp(): void
         ]);
     }
 
+    public function test_it_should_throw_an_invalid_argument_exception_when_the_specification_array_does_contain_invalid_data(): void
+    {
+        self::expectException(InvalidArgumentException::class);
+
+        // @phpstan-ignore-next-line
+        new OrSpecification(['invalid']);
+    }
+
     public function test_it_should_return_true_when_the_candidate_matches_all_specifications(): void
     {
         // Act
diff --git a/tests/XorSpecificationTest.php b/tests/XorSpecificationTest.php
index 96fef84..c15e31f 100644
--- a/tests/XorSpecificationTest.php
+++ b/tests/XorSpecificationTest.php
@@ -4,6 +4,7 @@
 
 namespace Maartenpaauw\Specifications\Tests;
 
+use InvalidArgumentException;
 use Maartenpaauw\Specifications\XorSpecification;
 use PHPUnit\Framework\TestCase;
 use Workbench\App\LengthSpecification;
@@ -31,6 +32,14 @@ protected function setUp(): void
         ]);
     }
 
+    public function test_it_should_throw_an_invalid_argument_exception_when_the_specification_array_does_contain_invalid_data(): void
+    {
+        self::expectException(InvalidArgumentException::class);
+
+        // @phpstan-ignore-next-line
+        new XorSpecification(['invalid']);
+    }
+
     public function test_it_should_only_return_true_when_one_specification_is_satisfied(): void
     {
         $this->assertTrue($this->specification->isSatisfiedBy('HELLO'));