The present study examined fathers' daily parenting hassles and coping strategies to (a) determine their association with fathers' emotional expressiveness and (b) predict their sons' development of socioemotional competence. Fathers of 148 preschool-aged boys reported on their parenting hassles, coping strategies, and emotional expressiveness; mothers also reported on fathers' emotional expressiveness; and teachers reported on boys' socioemotional competence. Parenting hassles were associated with less rational, more emotional, and more avoidance coping as well as negative emotional expressiveness. More emotional and less rational coping responses were related to more negative expressiveness, whereas more rational, more emotional, and less coping were related to more positive expressiveness. Fathers' negative expressiveness was predictive of their sons being rated as more aggressive and disruptive by their teachers. In addition, fathers' parenting hassles and coping both predicted teacher ratings of their sons' aggressiveness. Implications of the findings are discussed. (Contains 4 tables.)