The aim of this study was to investigate the role of the temporoparietal junction (TPJ) during tasks of imitation and counter-imitation of observed actions. Twenty individuals participated in two experiments. One experiment was an imitation/counter-imitation task, requiring the participant to imitate or counter-imitate an observed movement. The second experiment required the participant to plan a movement, then to imitate an observed movement that could be either the same or different from that planned. In both experiments, participants executed the task in a baseline session and in a session following inhibitory trains of repetitive transcranial magnetic stimulation on the right TPJ and on the right ventral premotor cortex. In both experiments, repetitive transcranial magnetic stimulation of the right TPJ decreased reaction times of incongruent responses--that is, it facilitated the execution of movements different from those previously observed or planned. These findings provide an example of modulation of self-other interactions using noninvasive neuromodulation of the right TPJ.