diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index 9d2e8b2..7aadbcf 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -643,7 +643,7 @@
    calls to :func:`unsetenv` don't update ``os.environ``, so it is actually
    preferable to delete items of ``os.environ``.
 
-   .. availability:: most flavors of Unix, Windows.
+   .. availability:: most flavors of Unix.
 
 
 .. _os-newstreams: