diff --git a/zenmap/zenmap b/zenmap/zenmap
index f2b2ccfdc..ae9894ee2 100755
--- a/zenmap/zenmap
+++ b/zenmap/zenmap
@@ -133,6 +133,13 @@ def is_secure_dir(path, num_symlinks = 0):
 
     return True
 
+# Add the install_lib directory to sys.path, the list of directories searched
+# for modules, but don't do it if the directory or its parents may be writable
+# by other users. The following line is replaced by the installation program.
+INSTALL_LIB = None
+if INSTALL_LIB is not None and is_secure_dir(INSTALL_LIB):
+    sys.path.append(INSTALL_LIB)
+
 import zenmapGUI.App
 
 if __name__ == '__main__':