Treatment integrity is critical to realizing the effects of evidence-based programs and practices (EBPPs) that aim to promote student mental and behavioral health. Across disciplines, time is consistently referenced as one of the most significant barriers to successful implementation outcomes (e.g., treatment integrity) of EBPPs. However, there is limited to no research that has examined the relationship between time allocation, treatment integrity, and student outcomes, especially at the school organizational level. This study used data from 106 elementary schools implementing Tier 1 school-wide positive behavior interventions and supports to examine the associations among two types of time allocation (collaboration/planning and professional development), school-level treatment integrity, and suspension. Results supported significant associations between two types of time allocation and both implementation and student behavioral outcomes. Moreover, the mediation analysis suggested that treatment integrity mediated the relationship between both types of time allocation (collaboration/planning and professional development) and student behavioral outcomes at the school level. Limitations and implications for research and practice are discussed.