The study examined the associations between children’s temperamental characteristics and mothers’ parenting styles, and the mediating and moderating role of maternal well-being in these associations. Mothers of 152 Finnish first grade children (79 girls and 73 boys) filled in questionnaires measuring their parenting styles (i.e., affection, behavioral control, and psychological control) and psychological well-being (i.e., depressive symptoms and self-esteem), and their children’s temperament. The results showed that children’s low positivity was associated with low maternal affection, whereas children’s negative emotionality was associated with mothers’ high controlling attempts in terms of psychological and behavioral control. The impacts of children’s low levels of positivity and high levels of activity on mothers’ psychological control were mediated via maternal well-being: the more active and the less positive a mother perceived her child to be, the lower was her well-being and, consequently, the more psychological control she applied. Moderating effects of psychological well-being were not found.