“Youth-friendly” family planning services, services tailored to meet the particular sexual and reproductive health needs of young people (aged 10–24 years), may improve reproductive health outcomes, including reduction of unintended pregnancy. The objectives of this systematic review were to summarize the evidence of the effect of youth-friendly family planning services on reproductive health outcomes and to describe key characteristics of youth-friendly family planning interventions. The review, conducted in 2011, was used to inform national recommendations on quality family planning services.