diff --git a/boltons/tableutils.py b/boltons/tableutils.py
index b936fd3..2acdd28 100644
--- a/boltons/tableutils.py
+++ b/boltons/tableutils.py
@@ -101,7 +101,7 @@ class DictInputType(InputType):
         return isinstance(obj, Mapping)
 
     def guess_headers(self, obj):
-        return obj.keys()
+        return sorted(obj.keys())
 
     def get_entry(self, obj, headers):
         return [obj.get(h) for h in headers]