Child engagement has been defined as active participation in classroom routines, appropriate interactions with the environment and it also predicts academic achievement. Therefore, it is necessary to identify predictors of engagement over time. Moreover, cross-cultural data is needed to provide a global picture of the quality of Early Childhood Education and Care (ECEC) across countries. This study aims to describe the quality of Swedish preschool classrooms and its relationship with students' engagement over time. Data was collected from 165 preschool teachers in 55 preschool units in Sweden. Results show that all classroom-related variables (Emotional Support, Instructional Support and Classroom Organisation) have increased levels over time, while engagement remained stable. Three groups of preschool classroom units were identified with similar patterns of classroom quality over time (higher emotional support and lower instructional practice) and similar differences in level. Emotional Support was found to be the best predictor of student engagement over time. (author abstract)