diff --git a/src/CallbackValidator.php b/src/CallbackValidator.php
index 611a45e..ec31f5c 100644
--- a/src/CallbackValidator.php
+++ b/src/CallbackValidator.php
@@ -25,21 +25,38 @@ class CallbackValidator extends BaseValidator
     /** @var callable Validation callback */
     protected $callback;
 
+    /** @var bool Whether to cache the callback's result */
+    protected $cacheResult;
+
+    /** @var ?bool The result, if {@see self::$cacheResult} is `true` (default) */
+    protected $result;
+
     /**
      * Create a new callback validator
      *
      * @param callable $callback Validation callback
+     * @param boolean $cacheResult Whether to cache the callback's result
      */
-    public function __construct(callable $callback)
+    public function __construct(callable $callback, bool $cacheResult = true)
     {
         $this->callback = $callback;
+        $this->cacheResult = $cacheResult;
     }
 
     public function isValid($value)
     {
+        if ($this->result !== null) {
+            return $this->result;
+        }
+
         // Multiple isValid() calls must not stack validation messages
         $this->clearMessages();
 
-        return call_user_func($this->callback, $value, $this);
+        $valid = (bool) call_user_func($this->callback, $value, $this);
+        if ($this->cacheResult) {
+            $this->result = $valid;
+        }
+
+        return $valid;
     }
 }
diff --git a/tests/CallbackValidatorTest.php b/tests/CallbackValidatorTest.php
index 14dadac..d92c5dd 100644
--- a/tests/CallbackValidatorTest.php
+++ b/tests/CallbackValidatorTest.php
@@ -22,4 +22,34 @@ public function testWhetherValidationCallbackIsOnlyExecutedWhenIsValidIsCalled()
 
         $this->assertSame($messages, $validator->getMessages());
     }
+
+    public function testWhetherCallbackIsOnlyCalledAgainIfNotCached()
+    {
+        $count = 0;
+
+        $validator = new CallbackValidator(function ($value, CallbackValidator $validator) use (&$count) {
+            $count++;
+            return true;
+        });
+
+        $validator->isValid(true);
+        $validator->isValid(true);
+
+        $this->assertEquals(1, $count, 'The callback is called again even if the cache is enabled');
+    }
+
+    public function testWhetherCallbackIsCalledAgainIfCached()
+    {
+        $count = 0;
+
+        $validator = new CallbackValidator(function ($value, CallbackValidator $validator) use (&$count) {
+            $count++;
+            return true;
+        }, false);
+
+        $validator->isValid(true);
+        $validator->isValid(true);
+
+        $this->assertEquals(2, $count, 'The callback is not called again even if the cache is disabled');
+    }
 }