In this study, we present the conceptions about teamwork questionnaire designed to evaluate the conceptions that secondary students have about teamwork. Participants were 309 students aged 15-16 from eight secondary schools, seven from Barcelona and one from Girona (Spain). The original 27-item questionnaire was reduced according to expert assessment and exploratory factor analysis to 20 items related to three conceptions about teamwork: individualistic, complementary and cooperative. By scores of factor analysis, the results show that empirically there are these three conceptions about teamwork with an appropriate level of reliability and of construct validity according to the theoretical hypotheses. There is no gender difference, but there are differences regarding types of school. The results are discussed with an emphasis on the relevance of this questionnaire as an instrument to identify and train secondary students in the conceptions about teamwork.