Studies have found a relationship between pretend play and self-regulation both during and outside pretend play; however, very few have investigated these three variables simultaneously. Therefore, this study examined the relationship between the frequency of role-play (a type of pretend play), self-regulatory behaviour during role-play, and self-regulation in a classroom with 55 Japanese children aged 4-6. Teachers rated the frequency of role-play and self-regulation in classrooms, based on which we conducted observations to evaluate self-regulatory behaviour during role-play. Frequency of role-play and self-regulatory behaviour during role-play were associated with self-regulation in classrooms. However, the frequency of role-play was not associated with self-regulatory behaviour during role-play. The results suggest that children who frequently engage in pretend play do not necessarily demonstrate self-regulatory behaviours during pretend play.