Peer Educators's Knowledge Influencing Giving Information about Adolescent ReproductiveHealth in Kulon Progo; Peer education are needed to provide information on adolescentreproducyive health (ARH) to peers. Teens prefer to receive reproductive health information from peers. But ARH material presented by peer educators still incomplete. The objective is to determine the behavior of peer educators in providing reproductive health information to adolescents in high school students in Kulon Progo District of Yogyakarta. This research is a part of explanatory research with cross sectional design. The population in this study was peer educators in high school in Kulon Progo district of Yogyakarta as many as 81 people, sample of this research is the number of total population. Data collection instruments such as questionnaires. Data was analyzed by univariate, bivariate and multivariate analyzes.The results showed that peer educators well behave in providing information on ARH (51.9%) and were well missbehaved (48.1%). Peer educators behavior influenced by the knowledge adolescent reproductive health (OR=2.972), availability of facilities that support peer educators in providing information (OR=2.886. Advice for Department of Community, Village Governance, Women and Family Planning (BPMPDP dan KB) in Kulon Progo district of Yogyakarta to hold refreshing material ARH and assignments for peer educators and to increase an advocacy and socialization to the principal.