diff --git a/src/Map.php b/src/Map.php
index 02035db..3fc3d43 100644
--- a/src/Map.php
+++ b/src/Map.php
@@ -139,10 +139,10 @@ public function put($key, $value): MapInterface
     /**
      * @psalm-mutation-free
      */
-    public function get($key)
+    public function get(string $key)
     {
-        if (! array_key_exists($key, $this->data)) {
-            throw new OutOfBoundsException(sprintf('There is no value stored for provided key: %s', (string) $key));
+        if (! $this->has($key)) {
+            throw new OutOfBoundsException(sprintf('There is no value stored for provided key: %s', $key));
         }
 
         return $this->data[$key];
@@ -267,4 +267,12 @@ public function map(callable $callback): MapInterface
     {
         return new GenericMap(array_map($callback, $this->data));
     }
+
+    /**
+     * @psalm-mutation-free
+     */
+    public function has(string $key): bool
+    {
+        return array_key_exists($key, $this->data);
+    }
 }
diff --git a/src/MapInterface.php b/src/MapInterface.php
index cdf402a..2ba39e7 100644
--- a/src/MapInterface.php
+++ b/src/MapInterface.php
@@ -92,12 +92,11 @@ public function keys(): OrderedListInterface;
     public function put($key, $value): MapInterface;
 
     /**
-     * @psalm-param string $key
      * @psalm-return TValue
      * @throws OutOfBoundsException if key does not exist.
      * @psalm-mutation-free
      */
-    public function get($key);
+    public function get(string $key);
 
     /**
      * @psalm-param MapInterface<TValue> $other
@@ -124,4 +123,9 @@ public function intersectUserAssoc(
         ?callable $valueComparator = null,
         ?callable $keyComparator = null
     ): MapInterface;
+
+    /**
+     * @psalm-mutation-free
+     */
+    public function has(string $key): bool;
 }
diff --git a/tests/GenericMapTest.php b/tests/GenericMapTest.php
index f47c56d..0513d1d 100644
--- a/tests/GenericMapTest.php
+++ b/tests/GenericMapTest.php
@@ -467,4 +467,23 @@ public function testGetThrowsOutOfBoundsExceptionWhenKeyDoesNotExist(): void
         $this->expectException(OutOfBoundsException::class);
         $map->get('foo');
     }
+
+    public function testHasDetectsExistingKey(): void
+    {
+        $map = new GenericMap(['foo' => 'bar']);
+
+        self::assertTrue($map->has('foo'));
+    }
+
+    public function testHasReturnsFalseOnEmptyMap(): void
+    {
+        $map = new GenericMap([]);
+        self::assertFalse($map->has('foo'));
+    }
+
+    public function testHasReturnsFalseForDueToCaseSensitivity(): void
+    {
+        $map = new GenericMap(['foo' => 'bar']);
+        self::assertFalse($map->has('Foo'));
+    }
 }