Discourse and self-perceptions are likely to be related in bidirectional ways. That is, people's self-perceptions are likely to shape their discourse behavior, but their (and their partners') discourse behavior in turn will shape their subsequent self-perceptions. To provide empirical evidence for this proposal, we conducted a study in which pairs of friends (n = 21 pairs) encountered a computer game. One friend played the game while the other observed; subsequently, both were asked to jointly tell a third party about their experience with the game. The resulting conversations were coded for narrative and other contributions, and discourse elements were examined in relation to pre- and postparticipation perceptions of expertise at the game. Players produced more narrative contributions than observers but only when observers had low self-perceived expertise prior to the game. Observers' narrative contributions were linked to changes in the players' self-perceptions of game expertise from prior to postconversation. These findings show that self-perceptions of expertise both shape, and are shaped by, discourse behavior.