diff --git a/lib/matplotlib/axes.py b/lib/matplotlib/axes.py
index 9d3061f40985..73ace3338a92 100644
--- a/lib/matplotlib/axes.py
+++ b/lib/matplotlib/axes.py
@@ -2334,8 +2334,8 @@ def tick_params(self, axis='both', **kwargs):
         *which* : ['major' | 'minor' | 'both']
             Default is 'major'; apply arguments to *which* ticks.
 
-        *direction* : ['in' | 'out']
-            Puts ticks inside or outside the axes.
+        *direction* : ['in' | 'out' | 'inout']
+            Puts ticks inside the axes, outside the axes, or both.
 
         *length*
             Tick length in points.