This study examined the relationships between perceptions of group members' free riding and group outcomes using Mulvey and Klein's 1998 perceived free riding scale. In a laboratory study, three free riding conditions were created (no free riding, free riding, free riding with justification) in which 97 college students performed two short number-finding tasks as members of temporary ad hoc three-person groups. 55% of the students were male and the average age was 22.9 yr. (SD= 3.0). Participants' perceptions of free riding were negatively related to commitment to the assigned group goal, task performance, and goals for group performance and individual performance. In the condition wherein free riding was justified by low ability, participants set lower goals for their future task performance than did those in the other two conditions.