Collective efficacy of a team is an aspect of group dynamics which can be very important for the team's performance since it shows how the team works as a unit and how much each member believes in the team's capacities to organize and carry out actions so as to reach a goal. The following study is an analysis of the construct of collective efficacy in sports situations and its correlation with another important construct in sport psychology - the quality of coach-athlete relationship viewed from the perspective of an athlete. Self-perception and meta-perception of the coach-athlete relationship from the athlete's point of view is measured by means of the athlete version of the CART-Q (The Coach- Athlete Relationship Questionnaire, Jowett & Ntoumanis, 2004), whereas belief in collective efficacy of the team is measured by the CEQ (Collective Efficacy Questionnaire, Feltz & Rigg, 1998). The sample comprises 136 athletes from the age of 14 to 38, who are members of Serbia's top nine teams. The findings of this study confirm the hypothesis that the athlete's perception of the coach-athlete relationship predicts athlete's beliefs in collective efficacy. The athletes who assessed the relationship with their coach as harmonious (close, committed and complementary) had stronger belief in the team's collective efficacy than the athletes who qualified the relationship as less harmonious. .