diff --git a/src/load-path.cc b/src/load-path.cc
--- a/src/load-path.cc
+++ b/src/load-path.cc
@@ -444,7 +444,7 @@
     xpath += dir_path::path_sep_str + tpath;
 
   if (! sys_path.empty ())
-    xpath += sys_path;
+    xpath += dir_path::path_sep_str + sys_path;
 
   do_set (xpath, false);
 }