This paper discusses the use of role-playing in online mathematics teacher education for preparing pre-service secondary mathematics teachers to use formative feedback. Findings from video-recorded role-plays and participant reflections highlight how the context presented in the online role-plays can enable or restrict different types of feedback. The study also reveals that the online environment supports rehearsal for giving feedback but limits participants’ ability to express feedback. The paper offers suggestions for enhancing the potential of online role-playing for feedback rehearsal.