diff --git a/src/Base/SmartPtrPy.cpp b/src/Base/SmartPtrPy.cpp
index 5041d230e9..cd9757c929 100644
--- a/src/Base/SmartPtrPy.cpp
+++ b/src/Base/SmartPtrPy.cpp
@@ -26,6 +26,7 @@
 #endif
 
 #include "SmartPtrPy.h"
+#include "Interpreter.h"
 #include <CXX/Objects.hxx>
 
 
@@ -42,6 +43,7 @@ void SmartPtr::set(PyObject* pyob, bool owned)
 
 void SmartPtr::release()
 {
+    Base::PyGILStateLocker lock;
     Py::_XDECREF(p);
     p = nullptr;
 }