Purpose This study used a randomized control design to evaluate the effectiveness of AgTeen, an in‐home, family‐based farm safety intervention, in decreasing extra riding on tractors by youth. Having children as extra riders on tractors has deep roots in farm culture, but it can result in serious injury or death. Methods The study randomized 151 families into 3 groups: parent‐led intervention (fathers taught their families about farm safety), staff‐led intervention (staff members who were peer farmers taught families), and a no‐treatment control. Mothers, fathers, and all children aged 10‐19 participated in the lessons. Findings At study entry, 93% of youth reported that they had been an extra rider on a tractor in the past year. Although they were aware of the injury risk, fathers frequently gave tractor rides to their children. After the intervention, fathers in both AgTeen groups were less likely than control fathers to give youth tractor rides. Intervention youth were less likely than control youth to be extra riders. The intervention positively affected the extra‐riding attitudes and injury risk perceptions of mothers and fathers. The parent‐led and staff‐led groups did not significantly differ across study outcomes. Conclusions Findings confirm the effectiveness of a family‐based intervention in decreasing extra riding on tractors by youth.