Objective: This study aims investigate the moderating effect of mothers' overprotective parenting in the influence of young children's competence, as determined by their temperament, on mastery motivation. Methods: An online survey was conducted on 429 mothers with children aged 3-5. The collected data was analyzed using K-means clustering in SPSS 23.0 and the Process macro Model 2. Results: Children's temperaments were categorized into four types : easy-active temperament, easy-inactive temperament, slow temperament, and difficult temperament. It was confirmed that children's competence directly affected their mastery motivation when they had easy-inactive, slow, or difficult temperament. It was also found that mothers' intrusive control had a direct main effect on object persistence when children had easy temperament, while there was no effect on mastery pleasure. The moderating effects of mothers' anxious protection on the pathway from children's competence to object persistence were significant only among children with a slow temperament. Conclusion/Implications: This study highlights the need for mothers to adapt their parenting behavior to their children's temperament type. The study confirmed partial moderating effects of mothers' overprotective parenting in the influence of children's competence, as determined by their temperament, on mastery motivation.