The literature regarding teamwork has supported the idea that the key to improving team performance is to understand team processes. Early work within the realm of teamwork focused on quantifiable measures of team performance, like number of products developed. The measure of a successful team hinged on whether or not the team accomplished the end task. In more recent years, the focus has shifted to other measures of team functioning such as communication, problem solving, decision making, planning and task coordination, goal setting, and conflict resolution. The purpose of this study is to report the development and construct validity of an instrument to measure perceptions of engagement in teamwork among middle school aged youth.