Parental monitoring is defined as a set of behaviors used to gain knowledge about an adolescent's whereabouts, friends and associates, and activities. However, can knowledge of adolescents' whereabouts/activities, and friends all be attained through the same strategies? Or do they require their own strategies? This study used qualitative interviews with 173 parents of older adolescents from 100 ... [Show full abstract] families. Emergent themes described strategies by which parents gain information about their adolescents' friends and the substance use of those friends. The strategies included direct interaction with the friend, gaining information from the teen, using second-hand sources, and making assumptions. Some of these strategies were consistent with previous research, while others raise new questions and provide interesting new directions to pursue. Primarily, additional consideration needs to be given to assessments of parental monitoring that include strategies for gaining knowledge of adolescents' friends and their substance use.