Parent-adolescent emotion dynamics have attracted increasing attention in recent years because adolescence is a challenging period for both adolescents and parents. However, how emotions are coconstructed between parents and adolescents is less clear. This study examined whether mothers' and adolescents' emotion regulation strategy was linked with their own and each other's depression using the actor-partner interdependence model (APIM). The participants were 173 mother-adolescent pairs (Mother: Mage = 43.05 years old, SD = 3.78; Adolescent: Mage = 13.00 years old, SD = 0.90). The results showed that the more mothers used cognitive reappraisal, the lower their depression levels were; and the more mothers and adolescents used expressive suppression, the higher their levels of depression were. Additionally, maternal expressive suppression was associated with adolescent depressive symptoms. Moreover, the results revealed that for mothers with higher levels of expressive suppression, their adolescents' usage of expressive suppression was significantly positively related to adolescents' depression, while for those mothers with lower levels of expressive suppression, there was no significant correlation between adolescents' usage of expressive suppression and depression. The findings underscore the significance of recognising the interdependence and interconnected nature of emotions within parent-adolescent relationships for a comprehensive understanding of their emotional well-being.