diff --git a/lib/src/widgets/toolbar.dart b/lib/src/widgets/toolbar.dart
index e11d98d7..914de8ef 100644
--- a/lib/src/widgets/toolbar.dart
+++ b/lib/src/widgets/toolbar.dart
@@ -413,7 +413,7 @@ class QuillToolbar extends StatelessWidget implements PreferredSizeWidget {
 
   final List<Widget> children;
   final double toolBarHeight;
-  final double toolBarSectionSpacing;
+  final double? toolBarSectionSpacing;
   final bool? multiRowsDisplay;
 
   /// The color of the toolbar.