Preschool‐aged children are aware of differences in the race and abilities of the people around them. Given this awareness it is important to promote children's acceptance of diversity in the preschool period. The goals of this study were to assess the extent to which child care centres provide diversity instruction through classroom activities, materials and displays. The extent to which structural quality characteristics (e.g. staff training and education) contribute to diversity‐positive classrooms was also examined. Data were collected from 103 preschool classrooms in 64 child care centres serving a population of ethnically diverse families in Toronto, Canada. On average, these classrooms were found to be diversity‐positive environments. Hierarchical linear model analyses indicate that utilising a variety of teaching formats, higher salaries, greater supervision and having higher proportions of children who receive a child care subsidy predicted higher scores on a diversity instruction and materials index. This index was largely based on classroom observations. In contrast, lower levels of education and salary predicted staff reports of diversity‐promoting activities. These latter counter‐intuitive results are interpreted in light of potential self‐presentation biases.