Psychological well-being is contagious within families. However, two key issues remain unresolved: a) which type of well-being is transmitted and b) who transmits to whom The present study aims to answer these two questions by drawing on a longitudinal and nationally representative sample to examine a) whether both positive and negative aspects of well-being can be transmitted and b) whether both parents and children transmit well-being to each other. Analyses were conducted using the China Family Panel Studies data in 2010 (2971 adolescents and their parents) and 2014. Cross-lagged analysis showed that the positive aspect of well-being (i.e., subjective well-being, SWB) was almost fully transmitted among all family members. In contrast, the negative aspect of well-being (i.e., psychological distress, PD) was transmitted only from fathers to mothers and from fathers to adolescent children. A gender-specific effect emerged such that sons rather than daughters predicted fathers’ SWB. Well-being contagion in families was more robust for the positive aspect of well-being. Theoretical and practical implications are discussed.