The main purpose of this study was to design and validate a scale to assess the teamwork competency of undergraduate students (TCS, Teamwork Competency Scale). The research instrument designed and subjected to validation has nine specific dimensions: Collective effectiveness, learning orientation, group goal setting, planning and coordination, communication, conflict management, problem solving, performance monitoring and supportive behaviour. The instrument was validated using a sample of 802 first-year students at a university in Chile. The method of partial least squares (PLS) was used within a structural equation modelling (SEM) framework for statistical analysis. The results show that the TCS is a valid and reliable research instrument for the assessment of teamwork competency in undergraduate students.