Working time arrangements determine, to a large extent, the successful balancing of work and family life. This study investigates the role of working time preferences and hours mismatch for well-being among couples. The empirical evidence indicates that well-being is generally lower among those with working time mismatch. Particularly underemployment is detrimental for well-being. We further provide first evidence on spillovers from the partner's working time mismatch that are, however, no longer significant once we control for the partner's well-being. This suggests that well-being is contagious, and that the spillover is due to caring preferences.