diff --git a/boxedcpp/proxy_functions.hpp b/boxedcpp/proxy_functions.hpp
index 4453a35..9684ef9 100644
--- a/boxedcpp/proxy_functions.hpp
+++ b/boxedcpp/proxy_functions.hpp
@@ -98,6 +98,7 @@ struct Param_List_Builder
 class Proxy_Function
 {
   public:
+    virtual ~Proxy_Function() {}
     virtual Boxed_Value operator()(const std::vector<Boxed_Value> &params) = 0;
     virtual std::vector<Type_Info> get_param_types() = 0;
 
@@ -111,6 +112,8 @@ class Dynamic_Proxy_Function : public Proxy_Function
     {
     }
 
+    virtual ~Dynamic_Proxy_Function() {}
+
     virtual Boxed_Value operator()(const std::vector<Boxed_Value> &params)
     {
       return m_f(params);
@@ -134,6 +137,9 @@ class Proxy_Function_Impl : public Proxy_Function
     {
     }
 
+    virtual ~Proxy_Function_Impl() {}
+
+
     virtual Boxed_Value operator()(const std::vector<Boxed_Value> &params)
     {
       return call_func(m_f, params);