This study investigated risk and protective factors for marijuana use and problems with use in Ecuadorian girls in an attempt to inform this growing problem. Female secondary school students (N=16,310; M=15.02, SD=1.73 years) who completed the 2016 national survey of drug use participated. The likelihood of lifetime marijuana use, reported by 7.3% of the sample, was predicted by older age, greater perceived access to marijuana and affiliation with tobacco- and marijuana-using peers; aspects of parental monitoring and perceived physical safety in and around school were negatively related to the probability of use. Among girls reporting any marijuana use, age, frequency of past year use, ease of access and affiliation with marijuana-using peers was positively associated with marijuana use problems. These data support the roles of both parents and communities in reducing marijuana use among Ecuadorian girls and highlight the important role of peer influence.