diff --git a/src/myconvexproblem.hh b/src/myconvexproblem.hh
index b7c06e836ebc35d91fe51fe3fbf7b7925585e7ba..34f0f0fe0d86894486b6b4fdda51fad4aef15905 100644
--- a/src/myconvexproblem.hh
+++ b/src/myconvexproblem.hh
@@ -1,5 +1,8 @@
 // Based on dune/tnnmg/problem-classes/convexproblem.hh
 
+#ifndef MY_CONVEX_PROBLEM_HH
+#define MY_CONVEX_PROBLEM_HH
+
 #include <dune/istl/bcrsmatrix.hh>
 
 #include <dune/tnnmg/problem-classes/nonlinearity.hh>
@@ -53,3 +56,5 @@ class MyConvexProblem {
 
   VectorType& u;
 };
+
+#endif