diff --git a/dotnet/src/Agents/OpenAI/Extensions/KernelFunctionExtensions.cs b/dotnet/src/Agents/OpenAI/Extensions/KernelFunctionExtensions.cs
index c4acca58770f..1a4b6fc2fbf6 100644
--- a/dotnet/src/Agents/OpenAI/Extensions/KernelFunctionExtensions.cs
+++ b/dotnet/src/Agents/OpenAI/Extensions/KernelFunctionExtensions.cs
@@ -81,6 +81,11 @@ private static string ConvertType(Type? type)
             return "array";
         }
 
+        if (type == typeof(DateTime) || type == typeof(DateTimeOffset))
+        {
+            return "date-time";
+        }
+
         return Type.GetTypeCode(type) switch
         {
             TypeCode.SByte or TypeCode.Byte or
diff --git a/dotnet/src/Agents/UnitTests/OpenAI/Extensions/KernelFunctionExtensionsTests.cs b/dotnet/src/Agents/UnitTests/OpenAI/Extensions/KernelFunctionExtensionsTests.cs
index acf195840366..3710b4841ab3 100644
--- a/dotnet/src/Agents/UnitTests/OpenAI/Extensions/KernelFunctionExtensionsTests.cs
+++ b/dotnet/src/Agents/UnitTests/OpenAI/Extensions/KernelFunctionExtensionsTests.cs
@@ -58,7 +58,7 @@ public void TestFunction1() { }
         [KernelFunction]
         [Description("test description")]
 #pragma warning disable IDE0060 // Unused parameter for mock kernel function
-        public void TestFunction2(string p1, bool p2, int p3, string[] p4, ConsoleColor p5, OpenAIAssistantDefinition p6) { }
+        public void TestFunction2(string p1, bool p2, int p3, string[] p4, ConsoleColor p5, OpenAIAssistantDefinition p6, DateTime p7) { }
 #pragma warning restore IDE0060 // Unused parameter
     }
 }