diff --git a/autoload/UltiSnips/map_keys.vim b/autoload/UltiSnips/map_keys.vim
index 44e4082..eb570ba 100644
--- a/autoload/UltiSnips/map_keys.vim
+++ b/autoload/UltiSnips/map_keys.vim
@@ -1,6 +1,11 @@
 call UltiSnips#bootstrap#Bootstrap()
 
 function! UltiSnips#map_keys#MapKeys()
+    if !exists('g:_uspy')
+        " Do not map keys if bootstrapping failed (e.g. no Python).
+        return
+    endif
+
     " Map the keys correctly
     if g:UltiSnipsExpandTrigger == g:UltiSnipsJumpForwardTrigger