diff --git a/tornado/ioloop.py b/tornado/ioloop.py
index ec93518d0..d0965f8e4 100644
--- a/tornado/ioloop.py
+++ b/tornado/ioloop.py
@@ -654,7 +654,7 @@ def add_callback_from_signal(
     ) -> None:
         """Calls the given callback on the next I/O loop iteration.
 
-        Intended to be afe for use from a Python signal handler; should not be
+        Intended to be safe for use from a Python signal handler; should not be
         used otherwise.
 
         .. deprecated:: 6.4