diff --git a/src/Avalonia.Controls/TextBox.cs b/src/Avalonia.Controls/TextBox.cs
index 7cbf442d88..a5728d44ea 100644
--- a/src/Avalonia.Controls/TextBox.cs
+++ b/src/Avalonia.Controls/TextBox.cs
@@ -2183,7 +2183,7 @@ namespace Avalonia.Controls
                 textBuilder.Append(text);
                 textBuilder.Remove(start, end - start);
 
-                SetCurrentValue(TextProperty, textBuilder.ToString());
+                SetCurrentValue(TextProperty, StringBuilderCache.GetStringAndRelease(textBuilder));
 
                 _presenter?.MoveCaretToTextPosition(start);