During adolescence, youth increase in both independence and conflict with parents. Parents vary in how much they know about their adolescents' whereabouts and activities and how they acquire this information (i.e., the sources of what parents know). We probed how parental knowledge of adolescents' whereabouts and activities-and their information sources-relates to (a) domains of parent-adolescent conflict (fighting about, or having different beliefs about, daily life topics) and (b) parent and adolescent attachment-related behavior during a conflict discussion task. Using the Actor-Partner Interdependence Model, we tested links between parental knowledge and its sources and conflict processes. Eighty-seven adolescents (Mage = 15.18; 55% female) and parents completed surveys about parental knowledge and its sources (i.e., parental solicitation of adolescents' activities, adolescent disclosure to parents about their activities) and separate interviews on conflict domains. A subset of parent-adolescent dyads (n = 65) interacted for 5 min about an adolescent-identified conflict topic. Different beliefs about daily life topics related to parental knowledge: parents' reports of greater different beliefs about daily life topics predicted less knowledge of adolescents' activities/whereabouts, solicitation, and disclosure, for both parent and adolescent reports of these domains. For adolescents, greater different beliefs related to less solicitation and disclosure. Only adolescent reports of parental knowledge, solicitation, and disclosure predicted attachment-related behaviors both dyad members displayed during the conflict discussion task. Findings reveal links between parental knowledge of adolescents' activities and conflict processes and demonstrate dyadic interdependence between parental knowledge of adolescents' activities and conflict processes. (PsycInfo Database Record (c) 2024 APA, all rights reserved).