People spontaneously adjust their emotions to others when they interact. This temporal coupling of emotions is an adaptive process facilitating social bonding. The present study examined differences in coupling patterns during parent-child versus peer interactions in adolescence, a developmental period marked by evolving parent-child dynamics and bond formation with peers. Because adolescents prioritize peer bonding while gradually asserting their autonomy from parental influence, we hypothesized that peer dyads showed stronger coupling than parent-adolescent dyads. Adolescents (age 16) with diverse ethnic backgrounds (N = 615; 50.2% female; 46.8% European American, 31.2% African American, 5.0% Hispanic, 3.0% Asian or Pacific Islander, 2.0% Native American, and 12.0% multiple ethnic backgrounds) participated in two videotaped interaction tasks: one with a parent and one with a self-nominated peer. Parent and peer interactions included discussions on positive and negative topics. Both dyad members' emotions were coded in real time. Cross-recurrence quantification analyses and growth-curve modeling revealed concurrent emotion coupling patterns, with peer dyads showing stronger coupling than parent-adolescent dyads. Moreover, peer dyads showed the most pronounced coupling patterns when they discussed personal problems, while parent-adolescent dyads showed the most pronounced coupling patterns when they discussed the planning of a fun activity. Our findings emphasize the importance of microlevel emotion dynamics in understanding larger scale developmental shifts in relationships during adolescence. (PsycInfo Database Record (c) 2024 APA, all rights reserved).