This paper examines the role of teachers in the implementation of citizenship education in Colombia. Consistent with its highly-decentralized school system, Colombia's National Program of Citizenship Competencies was developed with the participation of many local, national, and international partners. Among the most involved and most critical participants were the primary implementers of the reform: teachers. Teacher training is important to student achievement, but in a context that also seeks to teach democratic citizenship, training must be attentive to reciprocal learning and shared leadership. This paper highlights the impact of teacher training in one rural department and how a cross-cultural collaboration between Colombian and US-based educators benefited practitioners on both sides. Four key lessons on the design and delivery of professional development on citizenship education (and more broadly) are offered for educators and policymakers: the use of democratic pedagogy; the promotion and extension of teachers' self-awareness; the cross-pollination of perspectives across all levels; and a humble and inclusive expertise. (Contains 1 figure and 10 footnotes.)