diff --git a/src/Microsoft.TestPlatform.PlatformAbstractions/Interfaces/System/PlatformArchitecture.cs b/src/Microsoft.TestPlatform.PlatformAbstractions/Interfaces/System/PlatformArchitecture.cs
index 990f4a1d42..2c7db68f75 100644
--- a/src/Microsoft.TestPlatform.PlatformAbstractions/Interfaces/System/PlatformArchitecture.cs
+++ b/src/Microsoft.TestPlatform.PlatformAbstractions/Interfaces/System/PlatformArchitecture.cs
@@ -11,6 +11,7 @@ public enum PlatformArchitecture
         X86,
         X64,
         ARM,
-        ARM64
+        ARM64,
+        S390x
     }
 }
diff --git a/src/Microsoft.TestPlatform.PlatformAbstractions/netcore/System/PlatformEnvironment.cs b/src/Microsoft.TestPlatform.PlatformAbstractions/netcore/System/PlatformEnvironment.cs
index f791c2f759..ed2f902844 100644
--- a/src/Microsoft.TestPlatform.PlatformAbstractions/netcore/System/PlatformEnvironment.cs
+++ b/src/Microsoft.TestPlatform.PlatformAbstractions/netcore/System/PlatformEnvironment.cs
@@ -28,6 +28,12 @@ public PlatformArchitecture Architecture
                         return PlatformArchitecture.ARM;
                     case System.Runtime.InteropServices.Architecture.Arm64:
                         return PlatformArchitecture.ARM64;
+
+                    // The symbolic value is only available with .NET 6
+                    // preview 6 or later, so use the numerical value for now.
+                    // case System.Runtime.InteropServices.Architecture.S390x:
+                    case (Architecture)5:
+                        return PlatformArchitecture.S390x;
                     default:
                         throw new NotSupportedException();
                 }