Psychological well-being is contagious in families. The present study aims to examine a) whether both positive versus negative aspects of well-being can be transmitted and b) whether both parents and children transmit well-being to each other by drawing on a longitudinal and nationally representative sample. Cross-lagged models showed that the positive aspect of well-being (i.e., subjective well-being) was almost fully transmitted among all family members. In contrast, the negative aspect of well-being (i.e., psychological distress) was transmitted only from fathers to mothers and from fathers to adolescent children. The study indicates that well-being contagion in families was more robust for the positive aspect of well-being. Theoretical and practical implications are discussed.