The present study explored relations among language skills, private speech, and self-regulation in three- to five-year-old children. Language skills were assessed with a standardised measure of language ability and by teacher reports of adaptive use of language in the classroom. Private speech was measured by observing children during a challenging task and by asking teachers to report on children's typical use of private speech. Teachers also reported on children's self-regulation. Results indicated that language skills were positively related to self-regulation. However, private speech, particularly private speech that was relevant to the task, was negatively related to language skills and to self-regulation. The frequency of relevant private speech mediated the association between language ability and self-regulation. Children who had higher language skills used less private speech and, in turn, had better self-regulation. The adaptive use of language for self-regulation is discussed in light of these findings.