Background: Exclusionary discipline (e.g. suspension and expulsion) is associated with lower student achievement, drop-out, and involvement in the juvenile justice system. Recently, states and school districts have begun to restrict exclusionary discipline, but there remains much to be learned about the potential impact on students. Research Design: I use a comparative interrupted time series to estimate whether a state policy prohibiting out-of-school suspension as a consequence for truancy affected student achievement, attendance, truancy, or disciplinary referrals. Findings: After testing a variety of specifications checks, I find evidence of slight increases in attendance, particularly for disadvantaged students, with suggestive evidence of improvements in test scores and reductions in disciplinary referrals for some students. Conclusions: These improvements were quite modest relative to what we might expect from an intuitively appealing policy and were likely influenced by incomplete compliance, particularly in areas serving more students from traditionally disadvantaged backgrounds. Implications for policy design and school leadership are discussed.