diff --git a/PolyShim/Net50/OperatingSystem.cs b/PolyShim/Net50/OperatingSystem.cs
index c58fbc2..3aabbc9 100644
--- a/PolyShim/Net50/OperatingSystem.cs
+++ b/PolyShim/Net50/OperatingSystem.cs
@@ -5,6 +5,7 @@
 using System;
 using System.Runtime.InteropServices;
 using System.Diagnostics.CodeAnalysis;
+using System.Runtime.Versioning;
 
 #if !POLYSHIM_INCLUDE_COVERAGE
 [ExcludeFromCodeCoverage]
@@ -16,20 +17,25 @@ internal static class MemberPolyfills_Net50_OperatingSystem
         // Can only detect the platform on .NET Standard 1.3+
 #if !NETSTANDARD || NETSTANDARD1_3_OR_GREATER
         // https://learn.microsoft.com/dotnet/api/system.operatingsystem.isfreebsd
+        [SupportedOSPlatformGuard("freebsd")]
         public static bool IsFreeBSD() => RuntimeInformation.IsOSPlatform(OSPlatform.FreeBSD);
 
         // https://learn.microsoft.com/dotnet/api/system.operatingsystem.islinux
+        [SupportedOSPlatformGuard("linux")]
         public static bool IsLinux() => RuntimeInformation.IsOSPlatform(OSPlatform.Linux);
 
         // https://learn.microsoft.com/dotnet/api/system.operatingsystem.ismacos
+        [SupportedOSPlatformGuard("macos")]
         public static bool IsMacOS() => RuntimeInformation.IsOSPlatform(OSPlatform.OSX);
 
         // https://learn.microsoft.com/dotnet/api/system.operatingsystem.iswindows
+        [SupportedOSPlatformGuard("windows")]
         public static bool IsWindows() => RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
 
         // Can only detect OS version on .NET Standard 2.0+ and .NET Core 2.0
 #if (!NETSTANDARD || NETSTANDARD2_0_OR_GREATER) && (!NETCOREAPP || NETCOREAPP2_0_OR_GREATER)
         // https://learn.microsoft.com/dotnet/api/system.operatingsystem.iswindowsversionatleast
+        [SupportedOSPlatformGuard("windows")]
         public static bool IsWindowsVersionAtLeast(int major, int minor = 0, int build = 0, int revision = 0)
         {
             if (!IsWindows())