diff --git a/simgear/io/sg_socket.hxx b/simgear/io/sg_socket.hxx
index c43a7c62..e775eb3b 100644
--- a/simgear/io/sg_socket.hxx
+++ b/simgear/io/sg_socket.hxx
@@ -33,7 +33,7 @@
 
 #include STL_STRING
 
-#include <simgear/math/fg_types.hxx>
+#include <simgear/math/sg_types.hxx>
 
 #include "iochannel.hxx"