diff --git a/src/sylvan_obj.cpp b/src/sylvan_obj.cpp
index 1503a215..fc4199f5 100644
--- a/src/sylvan_obj.cpp
+++ b/src/sylvan_obj.cpp
@@ -754,6 +754,13 @@ Mtbdd::operator=(const Mtbdd& right)
     return *this;
 }
 
+Mtbdd&
+Mtbdd::operator=(Mtbdd&& right)
+{
+  mtbdd = right.mtbdd;
+  return *this;
+}
+
 Mtbdd
 Mtbdd::operator!() const
 {
diff --git a/src/sylvan_obj.hpp b/src/sylvan_obj.hpp
index e118ad5c..294fafe9 100644
--- a/src/sylvan_obj.hpp
+++ b/src/sylvan_obj.hpp
@@ -717,6 +717,7 @@ class Mtbdd {
     bool operator==(const Mtbdd& other) const;
     bool operator!=(const Mtbdd& other) const;
     Mtbdd& operator=(const Mtbdd& right);
+    Mtbdd& operator=(Mtbdd&& right);
     Mtbdd operator!() const;
     Mtbdd operator~() const;
     Mtbdd operator*(const Mtbdd& other) const;