This chapter gives an overview of interaction techniques for mixed reality including augmented and virtual reality (AR/VR). Various modalities for input and output are discussed. Specifically, techniques for tangible and surface-based interaction, gesture-based, pen-based, gaze-based, keyboard and mouse-based, as well as haptic interaction are discussed. Furthermore, the combination of multiple modalities in multisensory and multimodal interaction, as well as interaction using multiple physical or virtual displays, are presented. Finally, interaction with intelligent virtual agents is considered.