diff --git a/src/iOS/Avalonia.iOS/TextInputResponder.cs b/src/iOS/Avalonia.iOS/TextInputResponder.cs
index d5723d78f7..8862f4e392 100644
--- a/src/iOS/Avalonia.iOS/TextInputResponder.cs
+++ b/src/iOS/Avalonia.iOS/TextInputResponder.cs
@@ -445,7 +445,7 @@ partial class AvaloniaView
 
         UITextPosition IUITextInput.BeginningOfDocument => _beginningOfDocument;
 
-        private int DocumentLength => _client.SurroundingText.Text.Length + (_markedText?.Length ?? 0);
+        private int DocumentLength => (_client.SurroundingText.Text?.Length ?? 0) + (_markedText?.Length ?? 0);
         UITextPosition IUITextInput.EndOfDocument => new AvaloniaTextPosition(DocumentLength);
 
         UITextRange IUITextInput.MarkedTextRange