As school resource officer (SRO) programs continue to be widely implemented, there is concern that an increasing police presence at schools will "criminalize" student behavior by moving problematic students to the juvenile justice system rather than disciplining them at school. If true, this has serious implications for students and schools; yet research on this topic is limited and the discourse is often based on speculation or anecdotal evidence. To address this issue, this study evaluated the impact of SROs on school-based arrest rates by comparing arrests at thirteen schools with an SRO to fifteen schools without an SRO in the same district. Poisson and negative binomial regression models showed that having an SRO did not predict more total arrests, but did predict more arrests for disorderly conduct. Conversely, having an SRO decreased the arrest rate for assault and weapons charges. Implications of these findings for understanding SROs and their role in criminalizing student behavior are discussed.