This study examined whether kindergarten children's psychological needs satisfaction would mediate the relationships between parental scaffolding and children's use of self-regulated learning (SRL) strategic behaviours. One hundred and thirty Chinese kindergarten children and their parents participated in the study. Parental scaffolding and children's SRL strategic behaviours were respectively observed in parent-child interaction tasks and child-alone tasks. Drawing on self-determination theory (SDT), children's satisfaction of three basic needs for competence, autonomy, and relatedness was assessed using both behavioural observation and self-report measures. Among the three aspects of observed needs satisfaction, children's observed satisfaction of the need for competence was particularly important, mediating all the relationships between three aspects of parental scaffolding and three aspects of children's SRL strategic behaviours. Children's perceived needs satisfaction, despite having some correlations with parental scaffolding and children's SRL, did not mediate any relationships between parental scaffolding and children's SRL strategic behaviours, which further revealed limitations associated with using self-report measures with young children. The study provides preliminary evidence of the mediating role of psychological needs satisfaction in the relationships between parental scaffolding and children's SRL in problem-solving situations.