In early childhood classrooms, transitions are often targeted as times of the day during which teachers encounter problems with deficiencies in child engagement, as well as frequent occurrences of challenging behavior. Studies to date on improving child behavior during in-class transitions have focused on providing supports for individual children, as well as on reducing transition duration. The present study evaluated the effects of systematic transition strategies, as applied to three Head Start preschool classrooms during targeted in-class transitions. Strategies encompassed an accumulation of antecedent and consequent manipulations and were selected on the basis of environmental fit with individual classroom environments. Participants included three Head Start preschool teachers and their respective students, all three to five years of age. The dependent measures examined in the study included mean percent classroom engagement and percent occurrence of challenging behavior, measured across all phases of the study (i.e., baseline, coaching and independent implementation). Results, evaluated in a multiple baseline probe across classrooms, indicated that with implementation of systematic transition strategies, mean percentages of classroom engagement within intervention phases (i.e., coaching and independent implementation) were higher and relatively more stable than those observed in baseline, within and across all three participating classrooms. Furthermore, mean percent occurrences of challenging behavior were lower and relatively more stable within phases of intervention (i.e., coaching and independent implementation) than those observed in baseline, within and across all three participating classrooms. Data on the accuracy with which teachers implemented selected strategies (i.e., treatment integrity) were also documented and presented in the context of results obtained. Implications for future research are discussed, in light of the limitations and findings of the current investigation.