The main aim of this study was to examine the relationship between mothers’ life satisfaction and social support reported at Time 1, and their children’s well-being indicators (positive and negative affect, life satisfaction, and happiness) reported one year after (Time 2). The main analyses involved 629 mother-child pairs, with children (53.9% female), aged 8 to 13 years (M = 10.52, SD = 1.18). To test our hypotheses, we conducted a longitudinal two-wave analysis using structural equation modelling, in which we controlled for children’s age and gender, and initial levels of children’s well-being indicators at Time 1. The results demonstrated direct significant positive longitudinal association between mother’s life satisfaction at Time 1 and children’s life satisfaction at Time 2, but there was no significant longitudinal association between mother’s life satisfaction at Time 1 and children’s happiness, and positive and negative affect. However, the results showed that mothers’ social support boosts the positive effects of mothers’ life satisfaction on children’s positive affect and overall happiness. In conclusion, the findings suggest that whilst mother’s life satisfaction is directly associated with children’s life satisfaction in the longer term, mother’s social support can enhance the positive effects of mother’s life satisfaction on children’s overall happiness and positive affect.