The use of peer leaders as facilitators for smoking and alcohol abuse prevention with adolescents is one component of recently successful programs. Peer leaders are unique in their abilities to influence peer group behavior because they are members of the peer group, are credible role models and disseminators of social information, and utilize the same language as their peers. Peer leaders can be trained to modify environmental, personality, and behavioral factors that are predictive of alcohol use among adolescents, and become a viable alternative to teachers and adult leaders. The WHO Collaborative Study on Alcohol Education and Young People compared a peer-led alcohol educational program to a teacher-led program to no program in 25 schools in Australia, Chile, Norway, and Swaziland. The educational program emphasized refusal skills for alcohol use among 8th and 9th graders in the four countries. The peer-led educational program appears to be efficacious in reducing adolescent involvement with alcohol across a variety of settings, economies, and cultures. Peer leadership may be a particularly promising approach to prevention, theoretically and empirically.