This paper gives an overview of facial animation techniques. While facial animation is currently used in the entertainment and advertisement industry, it will become part of dialog systems in commercial applications. Animation techniques based on 3D models and image-based rendering are presented and evaluated by the following characteristics: automatism, realism and flexibility. While animation techniques based on 3D models provide for high flexibility and automatism, they often lack realism. Image-based techniques achieve photo realism, but lack in automatism and flexibility.