Educational efforts to reduce global rates of adolescent pregnancy vary widely with a significant deficiency in the domain of sex education facilitator training. In this study, we sought to establish a pilot approach to comprehensive sex education facilitator training in Riobamba, Ecuador. The approach was aligned with UNESCO recommendations for training facilitators using an adapted version of the U.S.-based Big Decisions curriculum. Four internationally recruited bilingual instructors led a six-day (27-hour) intensive training-of-facilitators programme with twenty trainees using the Big Decisions sex education curriculum. Quantitative and qualitative analyses were conducted using various approaches: anonymised and pre/post-self-assessments, daily feedback surveys of self and instructors, and facilitation practice evaluations. Responses to anonymised surveys indicated improved self-perceived confidence in teaching each curriculum section. More objective pre- and post-teach-back evaluations showed improved ability to teach randomly assigned lessons as assessed by trainers. The pedagogy of facilitator training in comprehensive sex education seeks to combine evidence-informed and culturally appropriate approaches to training facilitators under unique local conditions using adapted assessment tools. This project identified important culturally relevant insights relevant to the future training of comprehensive sex education facilitators working within culturally conservative communities, and Latin America in particular.