diff --git a/src/libraries/System.Private.CoreLib/src/System/EventHandler.cs b/src/libraries/System.Private.CoreLib/src/System/EventHandler.cs
index dba4aad09e45c8..35572083cffc64 100644
--- a/src/libraries/System.Private.CoreLib/src/System/EventHandler.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/EventHandler.cs
@@ -5,5 +5,17 @@ namespace System
 {
     public delegate void EventHandler(object? sender, EventArgs e);
 
-    public delegate void EventHandler<TEventArgs>(object? sender, TEventArgs e); // Removed TEventArgs constraint post-.NET 4
+    public delegate void EventHandler<in TEventArgs>(object? sender, TEventArgs e) // Removed TEventArgs constraint post-.NET 4
+        where TEventArgs : allows ref struct;
+
+    /// <summary>
+    /// Represents the method that will handle an event when the event provides data.
+    /// </summary>
+    /// <typeparam name="TSender">The type of the object raising the event.</typeparam>
+    /// <typeparam name="TEventArgs">The type of the event data generated by the event.</typeparam>
+    /// <param name="sender">The source of the event.</param>
+    /// <param name="e">An object that contains the event data.</param>
+    public delegate void EventHandler<in TSender, in TEventArgs>(TSender sender, TEventArgs e)
+        where TSender : allows ref struct
+        where TEventArgs : allows ref struct;
 }
diff --git a/src/libraries/System.Runtime/ref/System.Runtime.cs b/src/libraries/System.Runtime/ref/System.Runtime.cs
index 84742f4e9a03fe..7e6c6bf7992dd7 100644
--- a/src/libraries/System.Runtime/ref/System.Runtime.cs
+++ b/src/libraries/System.Runtime/ref/System.Runtime.cs
@@ -2789,7 +2789,8 @@ public partial class EventArgs
         public EventArgs() { }
     }
     public delegate void EventHandler(object? sender, System.EventArgs e);
-    public delegate void EventHandler<TEventArgs>(object? sender, TEventArgs e);
+    public delegate void EventHandler<in TEventArgs>(object? sender, TEventArgs e) where TEventArgs : allows ref struct;
+    public delegate void EventHandler<in TSender, in TEventArgs>(TSender sender, TEventArgs e) where TSender : allows ref struct where TEventArgs : allows ref struct;
     public partial class Exception : System.Runtime.Serialization.ISerializable
     {
         public Exception() { }