diff --git a/gtsam/linear/GaussianFactor.cpp b/gtsam/linear/GaussianFactor.cpp
index 341f03779..0802deff4 100644
--- a/gtsam/linear/GaussianFactor.cpp
+++ b/gtsam/linear/GaussianFactor.cpp
@@ -18,8 +18,6 @@
 
 // \callgraph
 
-#pragma once
-
 #include <gtsam/linear/GaussianFactor.h>
 #include <gtsam/linear/VectorValues.h>
 
@@ -32,4 +30,4 @@ namespace gtsam {
     return d;
   }
 
-}
\ No newline at end of file
+}