diff --git a/src/OpenApi/src/Extensions/OpenApiEndpointConventionBuilderExtensions.cs b/src/OpenApi/src/Extensions/OpenApiEndpointConventionBuilderExtensions.cs
index ac4b49ca8306..0f3ed82a2a3e 100644
--- a/src/OpenApi/src/Extensions/OpenApiEndpointConventionBuilderExtensions.cs
+++ b/src/OpenApi/src/Extensions/OpenApiEndpointConventionBuilderExtensions.cs
@@ -29,6 +29,7 @@ public static class OpenApiEndpointConventionBuilderExtensions
     /// </remarks>
     /// <param name="builder">The <see cref="IEndpointConventionBuilder"/>.</param>
     /// <returns>A <see cref="IEndpointConventionBuilder"/> that can be used to further customize the endpoint.</returns>
+    [Obsolete("WithOpenApi is deprecated and will be removed in a future release. For more information, visit https://aka.ms/aspnet/deprecate/002.", DiagnosticId = "ASPDEPR002")]
     [RequiresDynamicCode(TrimWarningMessage)]
     [RequiresUnreferencedCode(TrimWarningMessage)]
     public static TBuilder WithOpenApi<TBuilder>(this TBuilder builder) where TBuilder : IEndpointConventionBuilder
@@ -48,6 +49,7 @@ public static TBuilder WithOpenApi<TBuilder>(this TBuilder builder) where TBuild
     /// <param name="builder">The <see cref="IEndpointConventionBuilder"/>.</param>
     /// <param name="configureOperation">An <see cref="Func{T, TResult}"/> that returns a new OpenAPI annotation given a generated operation.</param>
     /// <returns>A <see cref="IEndpointConventionBuilder"/> that can be used to further customize the endpoint.</returns>
+    [Obsolete("WithOpenApi is deprecated and will be removed in a future release. For more information, visit https://aka.ms/aspnet/deprecate/002.", DiagnosticId = "ASPDEPR002")]
     [RequiresDynamicCode(TrimWarningMessage)]
     [RequiresUnreferencedCode(TrimWarningMessage)]
     public static TBuilder WithOpenApi<TBuilder>(this TBuilder builder, Func<OpenApiOperation, OpenApiOperation> configureOperation)
diff --git a/src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Extensions/OpenApiRouteHandlerBuilderExtensionTests.cs b/src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Extensions/OpenApiRouteHandlerBuilderExtensionTests.cs
index 7a518238d616..8c14337a69ed 100644
--- a/src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Extensions/OpenApiRouteHandlerBuilderExtensionTests.cs
+++ b/src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Extensions/OpenApiRouteHandlerBuilderExtensionTests.cs
@@ -1,6 +1,8 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+#pragma warning disable ASPDEPR002 // WithOpenApi is deprecated
+
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Routing;
diff --git a/src/ProjectTemplates/Web.ProjectTemplates/content/WebApi-CSharp/Program.MinimalAPIs.OrgOrIndividualB2CAuth.cs b/src/ProjectTemplates/Web.ProjectTemplates/content/WebApi-CSharp/Program.MinimalAPIs.OrgOrIndividualB2CAuth.cs
index 4e502393522f..415dc9b38f31 100644
--- a/src/ProjectTemplates/Web.ProjectTemplates/content/WebApi-CSharp/Program.MinimalAPIs.OrgOrIndividualB2CAuth.cs
+++ b/src/ProjectTemplates/Web.ProjectTemplates/content/WebApi-CSharp/Program.MinimalAPIs.OrgOrIndividualB2CAuth.cs
@@ -128,7 +128,6 @@
 #if (EnableOpenAPI)
 })
 .WithName("GetWeatherForecast")
-.WithOpenApi()
 .RequireAuthorization();
 #else
 })