diff --git a/dotnet/src/webdriver/Response.cs b/dotnet/src/webdriver/Response.cs
index 054fd7cebc881..2cbb0085b3ece 100644
--- a/dotnet/src/webdriver/Response.cs
+++ b/dotnet/src/webdriver/Response.cs
@@ -18,6 +18,7 @@
 
 using Newtonsoft.Json;
 using OpenQA.Selenium.Internal;
+using System;
 using System.Collections.Generic;
 using System.Globalization;