diff --git a/src/Math/Math.h b/src/Math/Math.h
index 8124b0a3b..2f11f3023 100644
--- a/src/Math/Math.h
+++ b/src/Math/Math.h
@@ -27,6 +27,7 @@ namespace Magnum { namespace Math {
 #ifndef DOXYGEN_GENERATING_OUTPUT
 /* Class Constants used only statically */
 
+template<class T> class Complex;
 template<class T> class Dual;
 template<class> class DualQuaternion;