diff --git a/docs/simple_traffic_shaping.xml b/docs/simple_traffic_shaping.xml
index 81e187999..b8142d2dd 100644
--- a/docs/simple_traffic_shaping.xml
+++ b/docs/simple_traffic_shaping.xml
@@ -268,7 +268,7 @@ eth0                   External</programlisting>
 
     <para>Simple Traffic Shaping is only appropriate on interfaces where
     output queuing occurs. As a consequence, you usually only use it on
-    extermal interfaces. There are cases where you may need to use it on an
+    external interfaces. There are cases where you may need to use it on an
     internal interface (a VPN interface, for example). If so, just add an
     entry to <ulink
     url="manpages/shorewall-tcinterfaces.html">shorewall-tcinterfaces</ulink>(5):</para>