diff --git a/Lib/plat-riscos/riscospath.py b/Lib/plat-riscos/riscospath.py
index c875a4f..27b5732 100644
--- a/Lib/plat-riscos/riscospath.py
+++ b/Lib/plat-riscos/riscospath.py
@@ -15,7 +15,7 @@
 # strings representing various path-related bits and pieces
 curdir = '@'
 pardir = '^'
-extsep = '.'
+extsep = '/'
 sep = '.'
 pathsep = ','
 defpath = '<Run$Dir>'