diff --git a/gtsam/linear/linearAlgorithms-inst.h b/gtsam/linear/linearAlgorithms-inst.h
index 5b1cef2ed..29e1e1096 100644
--- a/gtsam/linear/linearAlgorithms-inst.h
+++ b/gtsam/linear/linearAlgorithms-inst.h
@@ -16,6 +16,7 @@
  */
 
 #include <gtsam/linear/VectorValues.h>
+#include <gtsam/linear/GaussianConditional.h>
 #include <gtsam/base/treeTraversal-inst.h>
 
 #include <boost/optional.hpp>
@@ -136,4 +137,4 @@ namespace gtsam
       }
     }
   }
-}
\ No newline at end of file
+}