diff --git a/gtsam/nonlinear/NonlinearOptimizer.h b/gtsam/nonlinear/NonlinearOptimizer.h
index 4dd81c8d9..e1c722caf 100644
--- a/gtsam/nonlinear/NonlinearOptimizer.h
+++ b/gtsam/nonlinear/NonlinearOptimizer.h
@@ -109,6 +109,9 @@ public:
   /** An auto pointer to this class */
   typedef std::auto_ptr<const NonlinearOptimizer> auto_ptr;
 
+  /** A shared pointer to this class */
+  typedef boost::shared_ptr<const NonlinearOptimizer> shared_ptr;
+
   /** A const shared_ptr to a NonlinearFactorGraph */
   typedef boost::shared_ptr<const NonlinearFactorGraph> SharedGraph;