diff --git a/lib/multiselect.dart b/lib/multiselect.dart
index 1868631..6a987d3 100644
--- a/lib/multiselect.dart
+++ b/lib/multiselect.dart
@@ -89,7 +89,7 @@ class DropDownMultiSelect<T> extends StatefulWidget {
   final Widget Function(T option)? menuItembuilder;
 
   /// a function to validate
-  final String Function(T? selectedOptions)? validator;
+  final String? Function(T? selectedOptions)? validator;
 
   /// defines whether the widget is read-only
   final bool readOnly;
@@ -142,7 +142,19 @@ class _DropDownMultiSelectState<TState> extends State<DropDownMultiSelect<TState
               hint: widget.hint,
               style: widget.hintStyle,
               icon: widget.icon,
-              validator: widget.validator != null ? widget.validator : null,
+              // validator: widget.validator != null ? widget.validator : null,
+              validator: widget.validator != null
+    ? (TState? value) {
+        // Check if the value is null or empty
+        if (value == null || (value is Iterable && value.isEmpty)) {
+          return widget.validator!(null);
+        }
+
+        // Call the provided validator function
+        return widget.validator!(value);
+      }
+    : null,
+
               decoration: widget.decoration != null
                   ? widget.decoration
                   : InputDecoration(
diff --git a/pubspec.yaml b/pubspec.yaml
index 83f2fde..c46d405 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -10,7 +10,7 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
-  states_rebuilder: ^6.2.0
+  states_rebuilder: ^6.4.0
 
 dev_dependencies:
   flutter_test: