This study investigated the effects of lying on belief ratings for autobiographical childhood events. Participants lied by trying to convince the experimenter that likely events had not happened and that unlikely events had happened. Participants consistently lied, consistently told the truth, and alternated lying and truth telling across two sessions. Results showed that consistent false assents increased belief in those false events and that consistent false denials decreased belief in those true events. False denials had a larger influence on belief than did false assents. False assents that were told first were more likely to increase in belief than were false assents told in the second session. False denials decreased belief in the true event regardless of when they were told. These results suggest that lying influences confidence ratings both by increasing belief in a lied‐about event and by decreasing belief in a true event.