This case study analyses a professional development (PD) program in global citizenship education (GCE) that seeks to develop teacher education candidates' knowledge and capacities as global citizens during a one-year Bachelor of Education program. In particular, we explore how pre-service teachers perceived and experienced PD in GCE as a component of their professional learning and how this knowledge related to their understanding of curricula and pedagogical practices. First, we explore a model of effective PD and use this model to describe and analyze the GCE PD program, followed by a brief discussion of its context within the Faculty PD program; next, we outline the pre-service teachers' conceptions of PD in GCE; and finally, we suggest ways that PD for pre-service teachers can be enhanced to meet the specific curricular and pedagogical demands of GCE. Our findings suggest that best practices for PD in GCE include consistent use of pedagogies such as experiential learning and explicit modeling; targeted instruction in specific intellectual, affective, and action domains of GCE; providing pre-service teachers with opportunities to practice and reflect on the implementation of GCE in classroom settings; and developing collaborative networks of support. (Contains 4 tables.)