Against the background of numerous public and academic debates on declining birth-rates and problems of reconciling professional work and family life, the present research addresses the association between children and subjective well-being. Most people believe that parenthood should make us happy. Notwithstanding, happiness research suggests that children are not important for the well-being of people living in contemporary western societies: Children might at most have a slightly negative effect on parental well-being. However, a closer look at existing research reveals that some studies report positive effects of parenthood on subjective well-being while other studies report negative effects. The present research aims at contributing to the explanation of this variation in children?s effects. Therefore, in line with social ecological theory, we identify several factors on individual level, couple or family level, and societal level that might affect the association between children and subjective well-being. The respective hypotheses are proved by means of multilevel modeling and structural equation modeling using individual data from 30 countries participating in the European Value Study 2008/09 and couple data from a project covering three countries (Austria, Germany, and Switzerland). Results illustrate that both, factors on individual level as well as factors on societal level moderate the association between children and subjective well-being. On individual level, among other factors, the stage in one?s life (age) and partnership status proved to be relevant. On societal level, the welfare state based childcare system and dominant family values seem to be most important. In addition, individual level factors and processes on couple level mediate the association between children and subjective well-being. For example, the strain resulting from childcare that women feel indirectly affects men?s subjective well-being via relationship conflict perceived by men.