Falls from heights are a leading cause of morbidity and mortality among construction workers, especially inexperienced workers and those performing residential construction. This research reports changes in fall prevention behaviors following revision of fall prevention training in a union-based carpenters' apprenticeship program. We used a comprehensive needs assessment to identify gaps in apprentice carpenters' preparation to work at heights, used these results to guide a school-based fall prevention curriculum to fill these gaps, and measured the effects of the revised curriculum on knowledge, beliefs, and fall prevention behaviors.