diff --git a/dune/tectonic/globalnonlinearity.hh b/dune/tectonic/globalnonlinearity.hh
index d64d04bd7f0572dd5d15634fcdecbd8dd95c3f13..4010d6d64ee66fd2b66bcd3d58751a2d8637b3ee 100644
--- a/dune/tectonic/globalnonlinearity.hh
+++ b/dune/tectonic/globalnonlinearity.hh
@@ -60,7 +60,7 @@ class GlobalNonlinearity {
   }
 
   void addHessianIndices(Dune::MatrixIndexSet &indices) const {
-    for (int i = 0; i < indices.rows(); ++i)
+    for (size_t i = 0; i < indices.rows(); ++i)
       indices.add(i, i);
   }
 
diff --git a/src/one-body-sample.cc b/src/one-body-sample.cc
index 0bdc21b959f2dc941be87fe317d1afa0cfc83d01..1aac9192059fa5a05faf1faf7a5e3125a0975710 100644
--- a/src/one-body-sample.cc
+++ b/src/one-body-sample.cc
@@ -263,7 +263,7 @@ int main(int argc, char *argv[]) {
             leafView, p1Basis, neumannNodes, b4, neumannFunction, time);
         stiffnessMatrix.mmv(u4, b4);
         // Apply Dirichlet condition
-        for (int i = 0; i < finestSize; ++i)
+        for (size_t i = 0; i < finestSize; ++i)
           if (ignoreNodes[i].count() == dim) {
             dirichletFunction.evaluate(time, u4_diff[i][0]);
             u4_diff[i][0] /= refinement_factor;