Intergenerational transmission may be present in adolescents' sleep and mental health problems, but there is limited evidence currently available. The current study aimed to examine the effects of parental insomnia symptoms on adolescent insomnia and depressive symptoms. From 21 April to May 12, 2021, this study conducted a large-scale cross-sectional survey in south China, 68,751 valid child-parent matched data were collected. The current study measured parental insomnia symptoms, adolescent insomnia symptoms, adolescent depressive symptoms, and demographic characteristics. SPSS 27 statistical software was used to perform Chi-square analysis, binary logistic regression, and indirect effect testing. In this sample, maternal and paternal insomnia has a prevalence of 8.2 % and 7.5 %. Among adolescents whose mother or father had insomnia, the prevalence of insomnia reached to 15.7 % and 15.1 %, and the prevalence of depressive symptoms reached to 17.6 % and 15.6 %. Adolescents whose parents have insomnia were more likely to suffer from insomnia and depressive symptoms. Moreover, parents' insomnia positively influences adolescent depressive symptoms through the mediation of the child's insomnia. This study prompts a reevaluation of family health dynamics in clinical practice and public health policy, leading to a more holistic approach to addressing adolescent sleep patterns and depressive symptoms.