diff --git a/src/Servers/IIS/IIS/test/testassets/InProcessWebSite/Startup.WebSockets.cs b/src/Servers/IIS/IIS/test/testassets/InProcessWebSite/Startup.WebSockets.cs
index d0750ef81fd4..fda6e51107c4 100644
--- a/src/Servers/IIS/IIS/test/testassets/InProcessWebSite/Startup.WebSockets.cs
+++ b/src/Servers/IIS/IIS/test/testassets/InProcessWebSite/Startup.WebSockets.cs
@@ -120,7 +120,13 @@ private static async Task<WebSocket> Upgrade(HttpContext context)
 
         // Upgrade the connection
         Stream opaqueTransport = await upgradeFeature.UpgradeAsync();
-        Assert.Null(context.Features.Get<IHttpMaxRequestBodySizeFeature>().MaxRequestBodySize);
+
+        // In-process reads upgraded data through the same loop that enforces MaxRequestBodySize, so it
+        // must clear the limit. Out-of-process runs on Kestrel, which never enforces it once upgraded.
+        if (context.Features.Get<IServerVariablesFeature>() is not null)
+        {
+            Assert.Null(context.Features.Get<IHttpMaxRequestBodySizeFeature>().MaxRequestBodySize);
+        }
 
         // Get the WebSocket object
         var ws = WebSocket.CreateFromStream(opaqueTransport, isServer: true, subProtocol: null, keepAliveInterval: TimeSpan.FromMinutes(2));