diff --git a/include/osmium/memory/collection.hpp b/include/osmium/memory/collection.hpp
index 01b127dc..f96e9cea 100644
--- a/include/osmium/memory/collection.hpp
+++ b/include/osmium/memory/collection.hpp
@@ -35,6 +35,7 @@ DEALINGS IN THE SOFTWARE.
 
 #include <osmium/memory/item.hpp>
 
+#include <cassert>
 #include <iosfwd>
 #include <iterator>
 #include <type_traits>