Adolescence is a critical period during which interactions with parents and peers play key roles in shaping mental well-being, yet there is ongoing debate regarding their relative importance. To address this gap, this research examines the relationships among communication with parents, social interactions with peers, and adolescents' mental well-being using data from 33,824 Chinese adolescents (ages 10-18 years, Mage = 13.55, 47.43% female) across three data collection waves. A rando