The effect of teammate personality on team production

•We ask: do the “Big Five” personality traits of extroversion, agreeableness, conscientiousness, emotional stability, and openness affect productivity on joint team tasks?•We find: teammate conscientiousness has a small, positive impact on team performance in three-person teams.•Effect is evident holding teammate ability and gender fixed.•Suggestive evidence that effect operates through improved team functioning and sustained increases in team member effort.