Schools continue to rely on disciplinary exclusions as a consequence for behavioral rule violations, despite evidence that removing students from instruction for discipline purposes is associated with poor behavioral, academic, and social outcomes. School-wide positive behavior interventions and supports (SWPBIS) is one multitiered support framework used to prevent behavior problems while developing effective and efficient systems for intervening with students who require more support. Prior research suggests implementing Tier 1 of SWPBIS with fidelity is associated with reductions in disciplinary exclusions. In this study, we evaluated the additive effects of implementing Tier 1 and advanced tiers (i.e., Tiers 2 and 3) with fidelity compared with Tier 1 alone for 558 schools in California. Results indicate schools implementing all three tiers with fidelity had significantly lower rates of students receiving one out-of-school suspension, out-of-school suspension incidents, and referrals to law enforcement. We also discuss implications and recommendations for future research.