The present experiment examined the effect of self-awareness on adult perspective-taking and egocentrism. After having indicated their own opinion on an ecology-related topic, university students estimated a fellow student's opinion on the same matter. Participants did so either in front of a mirror or not, and either after having received a cue for the fellow student's most probable opinion—his perspective—or not, resulting in a 2 (self-awareness: low vs. high) x 2 (cue: yes vs. no) between persons design. As expected, self-aware participants were more likely to correctly estimate the fellow student's most probable opinion, reflecting perspective-taking, if a cue for his/her perspective was provided. Moreover, self-awareness also reduced participants' false consensus beliefs (i.e. egocentrism)—when they had a cue for the fellow student's perspective. The results conceptually replicate and extend previous findings on self-awareness, perspective-taking, and egocentrism.