diff --git a/src/WebEncoders/ref/Microsoft.Extensions.WebEncoders.csproj b/src/WebEncoders/ref/Microsoft.Extensions.WebEncoders.csproj
index 4fbb9b15e3e8..cf24f3bb7476 100644
--- a/src/WebEncoders/ref/Microsoft.Extensions.WebEncoders.csproj
+++ b/src/WebEncoders/ref/Microsoft.Extensions.WebEncoders.csproj
@@ -3,6 +3,7 @@
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
     <TargetFrameworks Condition="'$(DotNetBuildFromSource)' == 'true'">$(DefaultNetCoreTargetFramework)</TargetFrameworks>
+    <Nullable>annotations</Nullable>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.WebEncoders.netstandard2.0.cs" />
diff --git a/src/WebEncoders/ref/Microsoft.Extensions.WebEncoders.netcoreapp.cs b/src/WebEncoders/ref/Microsoft.Extensions.WebEncoders.netcoreapp.cs
index ad8e11a40eae..2fb36d283847 100644
--- a/src/WebEncoders/ref/Microsoft.Extensions.WebEncoders.netcoreapp.cs
+++ b/src/WebEncoders/ref/Microsoft.Extensions.WebEncoders.netcoreapp.cs
@@ -14,7 +14,7 @@ namespace Microsoft.Extensions.WebEncoders
     public sealed partial class WebEncoderOptions
     {
         public WebEncoderOptions() { }
-        public System.Text.Encodings.Web.TextEncoderSettings TextEncoderSettings { [System.Runtime.CompilerServices.CompilerGeneratedAttribute] get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute] set { } }
+        public System.Text.Encodings.Web.TextEncoderSettings? TextEncoderSettings { [System.Runtime.CompilerServices.CompilerGeneratedAttribute] get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute] set { } }
     }
 }
 namespace Microsoft.Extensions.WebEncoders.Testing
diff --git a/src/WebEncoders/ref/Microsoft.Extensions.WebEncoders.netstandard2.0.cs b/src/WebEncoders/ref/Microsoft.Extensions.WebEncoders.netstandard2.0.cs
index ad8e11a40eae..2fb36d283847 100644
--- a/src/WebEncoders/ref/Microsoft.Extensions.WebEncoders.netstandard2.0.cs
+++ b/src/WebEncoders/ref/Microsoft.Extensions.WebEncoders.netstandard2.0.cs
@@ -14,7 +14,7 @@ namespace Microsoft.Extensions.WebEncoders
     public sealed partial class WebEncoderOptions
     {
         public WebEncoderOptions() { }
-        public System.Text.Encodings.Web.TextEncoderSettings TextEncoderSettings { [System.Runtime.CompilerServices.CompilerGeneratedAttribute] get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute] set { } }
+        public System.Text.Encodings.Web.TextEncoderSettings? TextEncoderSettings { [System.Runtime.CompilerServices.CompilerGeneratedAttribute] get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute] set { } }
     }
 }
 namespace Microsoft.Extensions.WebEncoders.Testing
diff --git a/src/WebEncoders/src/Microsoft.Extensions.WebEncoders.csproj b/src/WebEncoders/src/Microsoft.Extensions.WebEncoders.csproj
index 9b8efbd16f5e..baed23277e08 100644
--- a/src/WebEncoders/src/Microsoft.Extensions.WebEncoders.csproj
+++ b/src/WebEncoders/src/Microsoft.Extensions.WebEncoders.csproj
@@ -9,6 +9,7 @@
     <PackageTags>aspnetcore</PackageTags>
     <IsPackable>true</IsPackable>
     <IsAspNetCoreApp>true</IsAspNetCoreApp>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/WebEncoders/src/WebEncoderOptions.cs b/src/WebEncoders/src/WebEncoderOptions.cs
index 2f5e770a0c37..190c4d487fab 100644
--- a/src/WebEncoders/src/WebEncoderOptions.cs
+++ b/src/WebEncoders/src/WebEncoderOptions.cs
@@ -16,6 +16,6 @@ public sealed class WebEncoderOptions
         /// <remarks>
         /// If this property is null, then the encoders will use their default allow lists.
         /// </remarks>
-        public TextEncoderSettings TextEncoderSettings { get; set; }
+        public TextEncoderSettings? TextEncoderSettings { get; set; }
     }
 }
diff --git a/src/WebEncoders/test/Microsoft.Extensions.WebEncoders.Tests.csproj b/src/WebEncoders/test/Microsoft.Extensions.WebEncoders.Tests.csproj
index 3bf6fc1c9cd1..57884af9763c 100755
--- a/src/WebEncoders/test/Microsoft.Extensions.WebEncoders.Tests.csproj
+++ b/src/WebEncoders/test/Microsoft.Extensions.WebEncoders.Tests.csproj
@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <TargetFrameworks>$(DefaultNetCoreTargetFramework);net472</TargetFrameworks>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>