diff --git a/Src/Newtonsoft.Json/JsonConverter.cs b/Src/Newtonsoft.Json/JsonConverter.cs
index 09317d08..457291d8 100644
--- a/Src/Newtonsoft.Json/JsonConverter.cs
+++ b/Src/Newtonsoft.Json/JsonConverter.cs
@@ -95,7 +95,7 @@ namespace Newtonsoft.Json
         /// <param name="writer">The <see cref="JsonWriter"/> to write to.</param>
         /// <param name="value">The value.</param>
         /// <param name="serializer">The calling serializer.</param>
-        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        public sealed override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
         {
             if (!(value != null ? value is T : ReflectionUtils.IsNullable(typeof(T))))
             {
@@ -120,7 +120,7 @@ namespace Newtonsoft.Json
         /// <param name="existingValue">The existing value of object being read.</param>
         /// <param name="serializer">The calling serializer.</param>
         /// <returns>The object value.</returns>
-        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        public sealed override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
         {
             bool existingIsNull = existingValue == null;
             if (!(existingIsNull || existingValue is T))
@@ -148,7 +148,7 @@ namespace Newtonsoft.Json
         /// <returns>
         /// 	<c>true</c> if this instance can convert the specified object type; otherwise, <c>false</c>.
         /// </returns>
-        public override bool CanConvert(Type objectType)
+        public sealed override bool CanConvert(Type objectType)
         {
             return typeof(T).IsAssignableFrom(objectType);
         }