diff --git a/src/Microsoft.Framework.Localization.Abstractions/StringLocalizerExtensions.cs b/src/Microsoft.Framework.Localization.Abstractions/StringLocalizerExtensions.cs
index 78ed2625a0..c3cd604ad6 100644
--- a/src/Microsoft.Framework.Localization.Abstractions/StringLocalizerExtensions.cs
+++ b/src/Microsoft.Framework.Localization.Abstractions/StringLocalizerExtensions.cs
@@ -1,6 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved. 
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information. 
 
+using Microsoft.Framework.Internal;
+
 namespace Microsoft.Framework.Localization
 {
     public static class StringLocalizerExtensions
@@ -10,7 +12,7 @@ namespace Microsoft.Framework.Localization
         /// </summary>
         /// <param name="name">The name of the string resource.</param>
         /// <returns>The string resource as a <see cref="LocalizedString"/>.</returns>
-        public static LocalizedString GetString(this IStringLocalizer stringLocalizer, string name)
+        public static LocalizedString GetString([NotNull] this IStringLocalizer stringLocalizer, [NotNull] string name)
         {
             return stringLocalizer[name];
         }
@@ -21,7 +23,7 @@ namespace Microsoft.Framework.Localization
         /// <param name="name">The name of the string resource.</param>
         /// <param name="arguments">The values to format the string with.</param>
         /// <returns>The formatted string resource as a <see cref="LocalizedString"/>.</returns>
-        public static LocalizedString GetString(this IStringLocalizer stringLocalizer, string name, params object[] arguments)
+        public static LocalizedString GetString([NotNull] this IStringLocalizer stringLocalizer, [NotNull] string name, params object[] arguments)
         {
             return stringLocalizer[name, arguments];
         }