diff --git a/PolyShim/Net50/OSPlatformAttribute.cs b/PolyShim/Net50/OSPlatformAttribute.cs
new file mode 100644
index 0000000..aec60df
--- /dev/null
+++ b/PolyShim/Net50/OSPlatformAttribute.cs
@@ -0,0 +1,18 @@
+#if (NETCOREAPP && !NET5_0_OR_GREATER) || (NETFRAMEWORK) || (NETSTANDARD)
+#nullable enable
+// ReSharper disable RedundantUsingDirective
+// ReSharper disable CheckNamespace
+// ReSharper disable InconsistentNaming
+// ReSharper disable PartialTypeWithSinglePart
+
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.Runtime.Versioning;
+
+// https://learn.microsoft.com/en-us/dotnet/api/system.runtime.versioning.osplatformattribute
+[ExcludeFromCodeCoverage]
+internal abstract class OSPlatformAttribute(string platformName) : Attribute
+{
+    public string PlatformName { get; } = platformName;
+}
+#endif
diff --git a/PolyShim/Net50/SupportedOSPlatformAttribute.cs b/PolyShim/Net50/SupportedOSPlatformAttribute.cs
new file mode 100644
index 0000000..6cd0c4e
--- /dev/null
+++ b/PolyShim/Net50/SupportedOSPlatformAttribute.cs
@@ -0,0 +1,31 @@
+#if (NETCOREAPP && !NET5_0_OR_GREATER) || (NETFRAMEWORK) || (NETSTANDARD)
+#nullable enable
+// ReSharper disable RedundantUsingDirective
+// ReSharper disable CheckNamespace
+// ReSharper disable InconsistentNaming
+// ReSharper disable PartialTypeWithSinglePart
+
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.Runtime.Versioning;
+
+// https://learn.microsoft.com/en-us/dotnet/api/system.runtime.versioning.supportedosplatformattribute
+[AttributeUsage(
+    AttributeTargets.Assembly
+        | AttributeTargets.Class
+        | AttributeTargets.Constructor
+        | AttributeTargets.Enum
+        | AttributeTargets.Event
+        | AttributeTargets.Field
+        | AttributeTargets.Interface
+        | AttributeTargets.Method
+        | AttributeTargets.Module
+        | AttributeTargets.Property
+        | AttributeTargets.Struct,
+    AllowMultiple = true,
+    Inherited = false
+)]
+[ExcludeFromCodeCoverage]
+internal class SupportedOSPlatformAttribute(string platformName)
+    : OSPlatformAttribute(platformName);
+#endif
diff --git a/PolyShim/Net50/TargetPlatformAttribute.cs b/PolyShim/Net50/TargetPlatformAttribute.cs
new file mode 100644
index 0000000..79f0dbd
--- /dev/null
+++ b/PolyShim/Net50/TargetPlatformAttribute.cs
@@ -0,0 +1,16 @@
+#if (NETCOREAPP && !NET5_0_OR_GREATER) || (NETFRAMEWORK) || (NETSTANDARD)
+#nullable enable
+// ReSharper disable RedundantUsingDirective
+// ReSharper disable CheckNamespace
+// ReSharper disable InconsistentNaming
+// ReSharper disable PartialTypeWithSinglePart
+
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.Runtime.Versioning;
+
+// https://learn.microsoft.com/en-us/dotnet/api/system.runtime.versioning.targetplatformattribute
+[AttributeUsage(AttributeTargets.Assembly)]
+[ExcludeFromCodeCoverage]
+internal class TargetPlatformAttribute(string platformName) : OSPlatformAttribute(platformName);
+#endif
diff --git a/PolyShim/Net50/UnsupportedOSPlatformAttribute.cs b/PolyShim/Net50/UnsupportedOSPlatformAttribute.cs
new file mode 100644
index 0000000..1a09db9
--- /dev/null
+++ b/PolyShim/Net50/UnsupportedOSPlatformAttribute.cs
@@ -0,0 +1,34 @@
+#if (NETCOREAPP && !NET5_0_OR_GREATER) || (NETFRAMEWORK) || (NETSTANDARD)
+#nullable enable
+// ReSharper disable RedundantUsingDirective
+// ReSharper disable CheckNamespace
+// ReSharper disable InconsistentNaming
+// ReSharper disable PartialTypeWithSinglePart
+
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.Runtime.Versioning;
+
+// https://learn.microsoft.com/en-us/dotnet/api/system.runtime.versioning.unsupportedosplatformattribute
+[AttributeUsage(
+    AttributeTargets.Assembly
+        | AttributeTargets.Class
+        | AttributeTargets.Constructor
+        | AttributeTargets.Enum
+        | AttributeTargets.Event
+        | AttributeTargets.Field
+        | AttributeTargets.Interface
+        | AttributeTargets.Method
+        | AttributeTargets.Module
+        | AttributeTargets.Property
+        | AttributeTargets.Struct,
+    AllowMultiple = true,
+    Inherited = false
+)]
+[ExcludeFromCodeCoverage]
+internal class UnsupportedOSPlatformAttribute(string platformName, string? message = null)
+    : OSPlatformAttribute(platformName)
+{
+    public string? Message { get; } = message;
+}
+#endif
diff --git a/PolyShim/Net60/SupportedOSPlatformGuardAttribute.cs b/PolyShim/Net60/SupportedOSPlatformGuardAttribute.cs
new file mode 100644
index 0000000..9631f60
--- /dev/null
+++ b/PolyShim/Net60/SupportedOSPlatformGuardAttribute.cs
@@ -0,0 +1,29 @@
+#if (NETCOREAPP && !NET6_0_OR_GREATER) || (NETFRAMEWORK) || (NETSTANDARD)
+#nullable enable
+// ReSharper disable RedundantUsingDirective
+// ReSharper disable CheckNamespace
+// ReSharper disable InconsistentNaming
+// ReSharper disable PartialTypeWithSinglePart
+
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.Runtime.Versioning;
+
+// https://learn.microsoft.com/en-us/dotnet/api/system.runtime.versioning.supportedosplatformguardattribute
+[AttributeUsage(
+    AttributeTargets.Field | AttributeTargets.Method | AttributeTargets.Property,
+    AllowMultiple = true,
+    Inherited = false
+)]
+[ExcludeFromCodeCoverage]
+internal class SupportedOSPlatformGuardAttribute(string platformName)
+    // OSPlatformAttribute's constructor is not accessible where that type is natively defined
+#if !(NETCOREAPP && NET5_0_OR_GREATER)
+    : OSPlatformAttribute(platformName);
+#else
+    : Attribute
+{
+    public string PlatformName { get; } = platformName;
+}
+#endif
+#endif
diff --git a/PolyShim/Net60/UnsupportedOSPlatformGuardAttribute.cs b/PolyShim/Net60/UnsupportedOSPlatformGuardAttribute.cs
new file mode 100644
index 0000000..b64ee0b
--- /dev/null
+++ b/PolyShim/Net60/UnsupportedOSPlatformGuardAttribute.cs
@@ -0,0 +1,29 @@
+#if (NETCOREAPP && !NET6_0_OR_GREATER) || (NETFRAMEWORK) || (NETSTANDARD)
+#nullable enable
+// ReSharper disable RedundantUsingDirective
+// ReSharper disable CheckNamespace
+// ReSharper disable InconsistentNaming
+// ReSharper disable PartialTypeWithSinglePart
+
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.Runtime.Versioning;
+
+// https://learn.microsoft.com/en-us/dotnet/api/system.runtime.versioning.unsupportedosplatformguardattribute
+[AttributeUsage(
+    AttributeTargets.Field | AttributeTargets.Method | AttributeTargets.Property,
+    AllowMultiple = true,
+    Inherited = false
+)]
+[ExcludeFromCodeCoverage]
+internal class UnsupportedOSPlatformGuardAttribute(string platformName)
+    // OSPlatformAttribute's constructor is not accessible where that type is natively defined
+#if !(NETCOREAPP && NET5_0_OR_GREATER)
+    : OSPlatformAttribute(platformName);
+#else
+    : Attribute
+{
+    public string PlatformName { get; } = platformName;
+}
+#endif
+#endif
diff --git a/PolyShim/Net70/ObsoletedOSPlatformAttribute.cs b/PolyShim/Net70/ObsoletedOSPlatformAttribute.cs
new file mode 100644
index 0000000..f8cab83
--- /dev/null
+++ b/PolyShim/Net70/ObsoletedOSPlatformAttribute.cs
@@ -0,0 +1,45 @@
+#if (NETCOREAPP && !NET7_0_OR_GREATER) || (NETFRAMEWORK) || (NETSTANDARD)
+#nullable enable
+// ReSharper disable RedundantUsingDirective
+// ReSharper disable CheckNamespace
+// ReSharper disable InconsistentNaming
+// ReSharper disable PartialTypeWithSinglePart
+
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.Runtime.Versioning;
+
+// https://learn.microsoft.com/en-us/dotnet/api/system.runtime.versioning.obsoletedosplatformattribute
+[AttributeUsage(
+    AttributeTargets.Assembly
+        | AttributeTargets.Class
+        | AttributeTargets.Constructor
+        | AttributeTargets.Enum
+        | AttributeTargets.Event
+        | AttributeTargets.Field
+        | AttributeTargets.Interface
+        | AttributeTargets.Method
+        | AttributeTargets.Module
+        | AttributeTargets.Property
+        | AttributeTargets.Struct,
+    AllowMultiple = true,
+    Inherited = false
+)]
+[ExcludeFromCodeCoverage]
+internal class ObsoletedOSPlatformAttribute(string platformName, string? message = null)
+    // OSPlatformAttribute's constructor is not accessible where that type is natively defined
+#if !(NETCOREAPP && NET5_0_OR_GREATER)
+    : OSPlatformAttribute(platformName)
+#else
+    : Attribute
+#endif
+{
+#if (NETCOREAPP && NET5_0_OR_GREATER)
+    public string PlatformName { get; } = platformName;
+#endif
+
+    public string? Message { get; } = message;
+
+    public string? Url { get; init; }
+}
+#endif