diff --git a/tabellio/searchform/form.py b/tabellio/searchform/form.py
index dba6855..3331583 100644
--- a/tabellio/searchform/form.py
+++ b/tabellio/searchform/form.py
@@ -541,6 +541,10 @@ class IGlobalSearchForm(interface.Interface):
                     value_type=schema.Choice(required=False,
                     source=possible_topics));
 
+    sort_on = schema.Choice(title=_(u'Sort By'), required=False,
+                default=_(u'Type'),
+                values=[_(u'Type'), _(u'Number'), _(u'Session')])
+
 
 class GlobalSearchForm(form.Form):
     fields = field.Fields(IGlobalSearchForm)