Research Findings: Although it is well documented that toy play and book sharing shape communication between adults and children in different ways, relatively few studies have compared teacher - child interactions in the two activities. The aim of this observational study was to describe and compare the conversational functions of teachers' and children's interactional contributions during book sharing and toy play. Examining dyads of five- to six-year-old children (N = 38) and their preschool teachers in the two activities, we found that the teachers produced significantly higher proportions of questions during toy play and higher proportions of statements during book sharing and that their questions tended to be more advanced (i.e. inferential) during book sharing compared to toy play. Moreover, sequential analyses of the immediate dependencies between the teachers' and children's contributions revealed that the teachers' statements were more likely to follow the children's questions during toy play than during book sharing, which may suggest more "back-and-forth" communication during play. Practice or Policy: The study findings indicate that toy play and book sharing provide children with complementary communication experiences and that the choice of activity may shape their opportunities to engage in educational dialogs.