Theory of mind (ToM), the ability to interpret one's own and others' mental states, is essential for social interaction; thus, it is important to promote the early development of ToM. The current study investigated (1) whether sociodramatic play (SDP) promotes the development of ToM in kindergarten children; (2) whether teachers' ToM coaching, as well as children's individual differences in language and executive function (EF), may influence how children benefit from SDP; and (3) whether SDP improves children's development in language and EF. Seventy-one kindergarteners (M age = 60.2 months, SD = 5.7) divided into 12 groups were randomly assigned to three conditions: free play, SDP, or SDP + ToM coaching. Each condition included four weekly sessions, 45 min per session. Before and after the training, children's ToM, language and EF were measured. The results showed that after children's individual differences in ToM were considered, (1) SDP positively predicted children's post-test ToM; (2) teachers' ToM-related guidance during SDP and children's pretest EF positively predicted the training effect of SDP on children's ToM; (3) teachers' ToM-related guidance during SDP, but not SDP alone, predicted children's post-test language; and (4) neither SDP nor teachers' ToM-related guidance during SDP predicted children's post-test EF. (author abstract)