Developing new software quickly, successfully, and at low cost is critical in organizations. Ways of assessing the effectiveness of development teams has highlighted measures of factors, such as teamwork, group cohesiveness, and team integration, but the use of group potency theory (the collective belief of a group that it can be effective) is rare. In our study, we investigated antecedents of and consequences to group potency in software development project teams. By examining 53 software development project teams collected from small and medium-sized software firms in Turkey, we found, that team potency positively affected speed-to-market, development cost, and market success of the product. We also found that trust among project team members, past experiences of the members, and team empowerment had a positive impact on the team potency during the project. Managerial and theoretical implications are discussed. (C) 2007 Elsevier B.V. All rights reserved.