Public schools face difficult decisions on how to pare budgets. In the current financial environment, school districts employ a variety of policies to close budget gaps and stave off teacher layoffs and furloughs. An increasing number of schools are implementing four-day school weeks hoping to reduce overhead and transportation costs. The four-day-week policy requires substantial schedule changes as schools must increase the length of their school day to meet state-mandated minimum instructional hour requirements. Although some schools have indicated that this policy eases financial pressures, it is unknown whether the restructured schedule has an impact on student outcomes. In this study, we use school-level longitudinal data from the state of Colorado to investigate the relationship between the four-day school week and academic performance among elementary school students. We exploit the temporal and spatial variation in the four-day school week using a difference-in-differences empirical strategy. Our results suggest that student academic achievement has not been hurt by the change in schedule. Instead, the evidence indicates that the adoption of a four-day school week shares a positive and often statistically significant relationship with performance in both reading and mathematics; the math results in particular are generally robust to a range of specification checks. These findings have policy relevance to the current U.S. education system, where many school districts must cut costs. The four-day school week is a strategy currently under debate.2 "There's no way a switch like that wouldn't negatively affect teaching and learning." -Tim Callahan, spokesman for the Professional Association of Georgia Educators (Wall Street Journal)"We took our budget savings and plowed it right back into instructional content." -Riley Ramsey, Webster County, Kentucky school district director of personnel and technology (TIME Magazine)