Given the weaknesses that most current implementations of conver- sational virtual humans show, it is argued that future developments might benefit from the incorporation of a theory of mind. First, findings concerning the effects of current embodied agents´ communication will be presented. Then, basic principles of human communication are depicted. Drawing on models of perspective taking, common ground, imputing one´s knowledge to others and theory of mind, necessities for the human agent communication are derived. In the next step, recent implementations from various research groups are presented that take first steps into this direction. Finally, conclusions for future research are drawn.