diff --git a/test/mooneyrivlintest.cc b/test/mooneyrivlintest.cc
index 73fcfdd6b47e65f8618f95d620b4f826370e42b7..1134aa6ce283238c2a608bbfef07473fccf3f463 100644
--- a/test/mooneyrivlintest.cc
+++ b/test/mooneyrivlintest.cc
@@ -1,4 +1,5 @@
 #include <config.h>
+#include <iomanip>
 
 // Includes for the ADOL-C automatic differentiation library
 // Need to come before (almost) all others.