Research on the effectiveness of youth peer education programs (YPE) programs is scarce, and the wide variation in programs makes it difficult to generalize research findings. Measuring quality and comparing program effectiveness require the use of standardized instruments. In this study, the authors used standardized evidence-based instruments to compare program inputs, quality, outputs and outcomes for five YPE programs in Zambia. Clinic surveys were used to measure the following program outcomes: young people's exposure to the YPE programs, and referrals of young people to clinics for HIV/sexually transmitted infection testing and other reproductive health services. The study revealed wide variation in the cost, quality and outcomes of YPE programs. Higher quality programs were associated with greater exposure and more referrals of youth to the clinics. However, one of the two highest quality programs achieved twice as many exposure and referral outcomes at about half the cost per peer educator of the more expensive program. Results indicate that the standardized instruments used in this study are useful for assessing and comparing program attributes among diverse YPE programs.