With the growing interest in the development of purpose in youth, one important role that requires attention is the school teacher. The current paper explores student perceptions of the role teachers can play in fostering purpose in their students in the mid- and late adolescent years, and the teacher competencies which facilitate purpose development. The present investigation posits and tests a structural model in which student perceptions of teacher support predicts youth purpose, mediated by student perceptions of teacher competencies; in turn, youth purpose predicts broader positive youth development. Two samples of demographically diverse young people ages 13-18 were surveyed in the United States (n = 381) and Finland (n = 336). Results showed support for the role of teachers in fostering purpose, and provided evidence for the hypothesized model with some cross-cultural differences. Implications of these findings for developing purpose in schools are discussed.