Objective: To assess perceived implementation of 2 substance-abuse prevention programs: a standard one and a peer-led interactive one. Methods: Data from 16 health educators were collected after 504 classroom sessions, 63 of which were observed by 24 monitors. Results: In the interactive program, health educators (HEs) followed the curriculum less closely, reported less favorable classroom processes and less off-task talking than in the standard one. Conclusions: These data indicate that an interactive substance-abuse prevention program does not necessarily entail more off-task discussion but also does not necessarily guarantee more favorable program implementation.