The most important relationships in the life of the preschool children are their relationships with their parents. Until recently, when the child's relationship with their parents is considered, the relationship with their mother has been taken into account, while recently the father-child relationship has become one of the subjects that researchers are increasingly interested in and thus is emphasized. In this study, it was aimed to determine the mediating role of parenting efficacy in the association between father-child relationship and parental stress in preschool period. The research was carried out on fathers who have children between 48-72 months who continue preschool education. The study group consisted of 421 fathers selected among these fathers by random sampling method. Child-Parent Relationship Scale, Parenting Efficacy Scale and Parental Stress Scale were used to collect the research data. The results obtained from the research are as follows: Firstly, parental stress is a significant predictor of father-child relationship and parenting efficacy. Secondly, parenting efficacy is a significant predictor of father-child relationship. Finally, parenting efficacy has a partial mediating role in the relationship between father-child relationship and parenting efficacy. The results of the research may lead to the development of policies and practices that support parenting competence in terms of reducing the parental stress of fathers with preschool children and improving their relationship with their children.