diff --git a/Lib/imaplib.py b/Lib/imaplib.py
index d1f62b0..8734a84 100644
--- a/Lib/imaplib.py
+++ b/Lib/imaplib.py
@@ -751,7 +751,7 @@
                               ', '.join(Commands[command])))
         name = 'UID'
         typ, dat = self._simple_command(name, command, *args)
-        if command in ('SEARCH', 'SORT'):
+        if command in ('SEARCH', 'SORT', 'THREAD'):
             name = command
         else:
             name = 'FETCH'