diff --git a/addons/source-python/packages/source-python/cvars/__init__.py b/addons/source-python/packages/source-python/cvars/__init__.py
old mode 100644
new mode 100755
index 66177aede..516a2a380
--- a/addons/source-python/packages/source-python/cvars/__init__.py
+++ b/addons/source-python/packages/source-python/cvars/__init__.py
@@ -6,6 +6,8 @@
 # >> IMPORTS
 # =============================================================================
 # Source.Python Imports
+#   Core
+from core import AutoUnload
 #   Cvars
 from _cvars import ConVar
 from _cvars import _Cvar
@@ -24,5 +26,68 @@
 # >> ALL DECLARATION
 # =============================================================================
 __all__ = ('ConVar',
+           'ConVarChanged',
            'cvar',
            )
+
+
+# =============================================================================
+# >> CLASSES
+# =============================================================================
+class ConVarChanged(AutoUnload):
+    """ConVarChanged decorator class."""
+
+    def __init__(self, *convars):
+        """Store the convars."""
+        self._convars = ()
+        self.callback = None
+
+        # Validate convars
+        if not convars:
+            raise ValueError('At least one convar is required.')
+
+        _convars = []
+        for convar in convars:
+            if not isinstance(convar, (str, ConVar)):
+                raise ValueError('Given convar is not ConVar or ConVar name.')
+
+            elif isinstance(convar, str):
+                convar_name = convar
+                convar = cvar.find_var(convar_name)
+                if convar is None:
+                    raise ValueError(
+                        f'"{convar_name}" is not a valid ConVar name.')
+
+            _convars.append(convar)
+
+        self._convars = tuple(_convars)
+
+    def __call__(self, callback):
+        """Store the callback and add it to convars."""
+        # Is the callback callable?
+        if not callable(callback):
+            raise ValueError('Given callback is not callable.')
+
+        # Store the callback
+        self.callback = callback
+
+        # Loop through all convars
+        for convar in self._convars:
+
+            # Add the callback
+            convar.add_changed_callback(self.callback)
+
+        # Return the callback
+        return self.callback
+
+    def _unload_instance(self):
+        """Remove the callback from convars."""
+        # Was no callback registered?
+        if self.callback is None:
+            return
+
+        # Loop through all convars
+        for convar in self._convars:
+
+            # Remove the callback
+            convar.remove_changed_callback(self.callback)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
old mode 100644
new mode 100755
index 9bb21297a..889a15441
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -171,6 +171,7 @@ Set(SOURCEPYTHON_CVARS_MODULE_HEADERS
 )
 
 Set(SOURCEPYTHON_CVARS_MODULE_SOURCES
+    core/modules/cvars/cvars.cpp
     core/modules/cvars/cvars_wrap.cpp
 )
 
diff --git a/src/core/modules/cvars/cvars.cpp b/src/core/modules/cvars/cvars.cpp
new file mode 100755
index 000000000..0dc945a32
--- /dev/null
+++ b/src/core/modules/cvars/cvars.cpp
@@ -0,0 +1,217 @@
+/**
+* =============================================================================
+* Source Python
+* Copyright (C) 2012-2015 Source Python Development Team.  All rights reserved.
+* =============================================================================
+*
+* This program is free software; you can redistribute it and/or modify it under
+* the terms of the GNU General Public License, version 3.0, as published by the
+* Free Software Foundation.
+*
+* This program is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+* FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+* details.
+*
+* You should have received a copy of the GNU General Public License along with
+* this program.  If not, see <http://www.gnu.org/licenses/>.
+*
+* As a special exception, the Source Python Team gives you permission
+* to link the code of this program (as well as its derivative works) to
+* "Half-Life 2," the "Source Engine," and any Game MODs that run on software
+* by the Valve Corporation.  You must obey the GNU General Public License in
+* all respects for all other code used.  Additionally, the Source.Python
+* Development Team grants this exception to all derivative works.
+*/
+
+//-----------------------------------------------------------------------------
+// Includes.
+//-----------------------------------------------------------------------------
+#include "cvars.h"
+
+
+//-----------------------------------------------------------------------------
+// Global ConVar changed callback mapping.
+//-----------------------------------------------------------------------------
+typedef std::vector<object> ChangedCallbacks;
+typedef std::unordered_map<std::string, ChangedCallbacks> ConVarMap;
+ConVarMap g_ConVarMap;
+
+
+//-----------------------------------------------------------------------------
+// ConVar extension class.
+//-----------------------------------------------------------------------------
+boost::shared_ptr<ConVar> ConVarExt::__init__(const char* name, const char* value,
+	const char* description, int flags, object min_value, object max_value)
+{
+	if (!name || name[0] == '\0')
+		BOOST_RAISE_EXCEPTION(PyExc_ValueError, "An empty string is not a valid ConVar name.")
+
+	float fMin = 0;
+	float fMax = 0;
+
+	try {
+		fMin = extract<float>(min_value);
+	}
+	catch (...) {
+		PyErr_Clear();
+	}
+
+	try {
+		fMax = extract<float>(max_value);
+	}
+	catch (...) {
+		PyErr_Clear();
+	}
+
+	ConVar *pConVar = g_pCVar->FindVar(name);
+	if (!pConVar)
+	{
+		// Find if the command already exists
+		ConCommand* pConCommand = g_pCVar->FindCommand(name);
+		if (pConCommand)
+			BOOST_RAISE_EXCEPTION(PyExc_ValueError, "ConCommand already exists.")
+
+		ConVar* pConVar = new ConVar(strdup(name), strdup(value), flags,
+			strdup(description), !min_value.is_none(), fMin, !max_value.is_none(), fMax);
+
+		return boost::shared_ptr<ConVar>(pConVar, &NeverDeleteDeleter<ConVar *>);
+	}
+
+	return boost::shared_ptr<ConVar>(pConVar, &NeverDeleteDeleter<ConVar *>);
+}
+
+bool ConVarExt::HasMin(ConVar* pConVar)
+{
+	float fMin;
+	return pConVar->GetMin(fMin);
+}
+
+bool ConVarExt::HasMax(ConVar* pConVar)
+{
+	float fMax;
+	return pConVar->GetMax(fMax);
+}
+
+float ConVarExt::GetMin(ConVar* pConVar)
+{
+	float fMin;
+	pConVar->GetMin(fMin);
+	return fMin;
+}
+
+float ConVarExt::GetMax(ConVar* pConVar)
+{
+	float fMax;
+	pConVar->GetMax(fMax);
+	return fMax;
+}
+
+void ConVarExt::SetValue(ConVar* pConVar, bool bValue)
+{
+	pConVar->SetValue(bValue);
+}
+
+void ConVarExt::MakePublic(ConVar* pConVar)
+{
+	pConVar->m_nFlags |= FCVAR_NOTIFY;
+	g_pCVar->CallGlobalChangeCallbacks(pConVar, pConVar->GetString(), pConVar->GetFloat());
+}
+
+void ConVarExt::RemovePublic(ConVar* pConVar)
+{
+	pConVar->m_nFlags &= ~FCVAR_NOTIFY;
+	g_pCVar->CallGlobalChangeCallbacks(pConVar, pConVar->GetString(), pConVar->GetFloat());
+}
+
+void ConVarExt::ChangedCallback(IConVar* var, const char* pOldValue, float flOldValue)
+{
+	ConVarMap::iterator map_it = g_ConVarMap.find(var->GetName());
+	if (map_it == g_ConVarMap.end())
+		return;
+
+	ConVar* pConVar = static_cast<ConVar*>(var);
+
+	ChangedCallbacks& callables = map_it->second;
+	for (ChangedCallbacks::iterator it = callables.begin(); it != callables.end(); ++it)
+	{
+		BEGIN_BOOST_PY()
+			(*it)(ptr(pConVar), pOldValue, pConVar->GetString());
+		END_BOOST_PY_NORET()
+	}
+}
+
+void ConVarExt::AddChangedCallback(ConVar* pConVar, PyObject* pCallable)
+{
+	// Get the object instance of the callable
+	object oCallable = object(handle<>(borrowed(pCallable)));
+
+	ChangedCallbacks& callables = g_ConVarMap[pConVar->GetName()];
+	if (!callables.size())
+	{
+		if (!installed)
+		{
+			g_pCVar->InstallGlobalChangeCallback(ChangedCallback);
+			installed = true;
+		}
+	}
+	else
+	{
+		for (ChangedCallbacks::iterator it = callables.begin(); it != callables.end(); ++it)
+		{
+			if (is_same_func(oCallable, *it))
+				BOOST_RAISE_EXCEPTION(PyExc_ValueError, "Callback already registered.")
+		}
+	}
+
+	callables.push_back(oCallable);
+}
+
+void ConVarExt::RemoveChangedCallback(ConVar* pConVar, PyObject* pCallable)
+{
+	ConVarMap::iterator map_it = g_ConVarMap.find(pConVar->GetName());
+	if (map_it == g_ConVarMap.end())
+		BOOST_RAISE_EXCEPTION(PyExc_ValueError, "Callback not registered.")
+
+	// Get the object instance of the callable
+	object oCallable = object(handle<>(borrowed(pCallable)));
+
+	ChangedCallbacks& callables = map_it->second;
+	for (ChangedCallbacks::iterator it = callables.begin();;)
+	{
+		if(it == callables.end())
+			BOOST_RAISE_EXCEPTION(PyExc_ValueError, "Callback not registered.")
+
+		if (is_same_func(oCallable, *it))
+		{
+			callables.erase(it);
+			break;
+		}
+		else
+		{
+			++it;
+		}
+	}
+
+	if (!callables.size())
+	{
+		g_ConVarMap.erase(map_it);
+		if (!g_ConVarMap.size())
+		{
+			g_pCVar->RemoveGlobalChangeCallback(ChangedCallback);
+			installed = false;
+		}
+	}
+}
+
+void ConVarExt::ClearCallback()
+{
+	if (installed)
+	{
+		g_ConVarMap.clear();
+		g_pCVar->RemoveGlobalChangeCallback(ChangedCallback);
+		installed = false;
+	}
+}
+
+bool ConVarExt::installed = false;
diff --git a/src/core/modules/cvars/cvars.h b/src/core/modules/cvars/cvars.h
old mode 100644
new mode 100755
index bfa2079f2..8c9f1e4bb
--- a/src/core/modules/cvars/cvars.h
+++ b/src/core/modules/cvars/cvars.h
@@ -30,8 +30,17 @@
 //-----------------------------------------------------------------------------
 // Includes.
 //-----------------------------------------------------------------------------
+// C++
+#include <unordered_map>
+#include <vector>
+
+// This is required for accessing m_nFlags without patching convar.h
+#define private public
 #include "convar.h"
+#undef private
+
 #include "utilities/sp_util.h"
+#include "modules/listeners/listeners_manager.h"
 
 
 //-----------------------------------------------------------------------------
@@ -41,82 +50,25 @@ class ConVarExt
 {
 public:
 	static boost::shared_ptr<ConVar> __init__(const char* name, const char* value,
-		const char* description, int flags, object min_value, object max_value)
-	{
-		if (!name || name[0] == '\0')
-			BOOST_RAISE_EXCEPTION(PyExc_ValueError, "An empty string is not a valid ConVar name.")
-
-		float fMin = 0;
-		float fMax = 0;
-
-		try {
-			fMin = extract<float>(min_value);
-		}
-		catch (...) {
-			PyErr_Clear();
-		}
-
-		try {
-			fMax = extract<float>(max_value);
-		}
-		catch (...) {
-			PyErr_Clear();
-		}
-
-		ConVar *pConVar = g_pCVar->FindVar(name);
-		if (!pConVar)
-		{
-			ConVar* pConVar = new ConVar(strdup(name), strdup(value), flags,
-				strdup(description), !min_value.is_none(), fMin, !max_value.is_none(), fMax);
-
-			return boost::shared_ptr<ConVar>(pConVar, &NeverDeleteDeleter<ConVar *>);
-		}
-
-		return boost::shared_ptr<ConVar>(pConVar, &NeverDeleteDeleter<ConVar *>);
-	}
-
-	static bool HasMin(ConVar* pConVar)
-	{
-		float fMin;
-		return pConVar->GetMin(fMin);
-	}
+		const char* description, int flags, object min_value, object max_value);
 
-	static bool HasMax(ConVar* pConVar)
-	{
-		float fMax;
-		return pConVar->GetMax(fMax);
-	}
+	static bool HasMin(ConVar* pConVar);
+	static bool HasMax(ConVar* pConVar);
 
-	static float GetMin(ConVar* pConVar)
-	{
-		float fMin;
-		pConVar->GetMin(fMin);
-		return fMin;
-	}
+	static float GetMin(ConVar* pConVar);
+	static float GetMax(ConVar* pConVar);
 
-	static bool GetMax(ConVar* pConVar)
-	{
-		float fMax;
-		pConVar->GetMax(fMax);
-		return fMax;
-	}
+	static void SetValue(ConVar* pConVar, bool bValue);
 
-	static void SetValue(ConVar* pConVar, bool bValue)
-	{
-		pConVar->SetValue(bValue);
-	}
+	static void MakePublic(ConVar* pConVar);
+	static void RemovePublic(ConVar* pConVar);
 
-	static void MakePublic(ConVar* pConVar)
-	{
-		pConVar->m_nFlags |= FCVAR_NOTIFY;
-		g_pCVar->CallGlobalChangeCallbacks(pConVar, pConVar->GetString(), pConVar->GetFloat());
-	}
+	static void ChangedCallback(IConVar* var, const char* pOldValue, float flOldValue);
+	static void AddChangedCallback(ConVar* pConVar, PyObject* pCallable);
+	static void RemoveChangedCallback(ConVar* pConVar, PyObject* pCallable);
+	static void ClearCallback();
 
-	static void RemovePublic(ConVar* pConVar)
-	{
-		pConVar->m_nFlags &= ~FCVAR_NOTIFY;
-		g_pCVar->CallGlobalChangeCallbacks(pConVar, pConVar->GetString(), pConVar->GetFloat());
-	}
+	static bool installed;
 };
 
 
diff --git a/src/core/modules/cvars/cvars_wrap.cpp b/src/core/modules/cvars/cvars_wrap.cpp
old mode 100644
new mode 100755
index 997d410f6..f4d66b954
--- a/src/core/modules/cvars/cvars_wrap.cpp
+++ b/src/core/modules/cvars/cvars_wrap.cpp
@@ -299,7 +299,19 @@ void export_convar(scope _cvars)
 			&ConVarExt::RemovePublic,
 			"Remove the notify flag and make the console variable no longer public."
 		)
-			
+
+		.def("add_changed_callback",
+			&ConVarExt::AddChangedCallback,
+			"Add a callable object that will be called when the ConVar is changed.",
+			args("callable")
+		)
+
+		.def("remove_changed_callback",
+			&ConVarExt::RemoveChangedCallback,
+			"Remove a callable object that will be called when the ConVar is changed.",
+			args("callable")
+		)
+
 		// Special methods...
 		.def("__float__",
 			&ConVar::GetFloat,
diff --git a/src/core/sp_main.cpp b/src/core/sp_main.cpp
index 6f1be1dcb..5b0fdcf1b 100755
--- a/src/core/sp_main.cpp
+++ b/src/core/sp_main.cpp
@@ -58,6 +58,7 @@
 #include "manager.h"
 
 #include "modules/listeners/listeners_manager.h"
+#include "modules/cvars/cvars.h"
 #include "utilities/conversions.h"
 #include "modules/entities/entities_entity.h"
 #include "modules/core/core.h"
@@ -403,6 +404,9 @@ void CSourcePython::Unload( void )
 	DevMsg(1, MSG_PREFIX "Clearing convar changed listener...\n");
 	GetOnConVarChangedListenerManager()->clear();
 
+	DevMsg(1, MSG_PREFIX "Clearing convar changed callbacks...\n");
+	ConVarExt::ClearCallback();
+
 	DevMsg(1, MSG_PREFIX "Unhooking all functions...\n");
 	GetHookManager()->UnhookAllFunctions();