Rural youth in China experience numerous challenges during their transition into adulthood. Yet, research on this transition and its relevant influential factors is rare. Through the lens of family systems theory, this study examined the impacts of family dynamics (i.e., interparental and parent–adolescent interactions) in adolescence on the psychological adjustment of youth as they transition into adulthood. Participants were 1330 youth and their mothers in rural Gansu. In 2004, mothers completed questionnaires of interparental and parent–adolescent interactions when youth were adolescents (M
age = 15.03, SD = 1.15). In 2009, youth completed questionnaires of depression and self‐esteem when they were emerging adults (M
age = 20.03, SD = 1.15). Results of structural equation modelling suggested that while interparental interactions in adolescence were not associated with the psychological adjustment of youth in emerging adulthood, positive parent–adolescent interactions in adolescence predicted better psychological adjustment of youth in emerging adulthood. Furthermore, mediation analysis showed that although interparental interactions did not directly affect the psychological adjustment of youth, they were positively associated with parent–adolescent interactions, which in turn contributed to the psychological adjustment of youth. The results reveal an enduring influence of family dynamics on psychological adjustment among rural Chinese youth during the transition into adulthood.