School transportation may increase student outcomes by providing a reliable and safe means of getting to and from school. Little evidence of the effects of such policies exists. In this paper, I provide some of the first causal evidence of transportation impacts on student attendance and achievement using a rich panel of student-level enrollment and address data for Michigan public school students and a unique dataset of district transportation policies for the largest 50 districts in Michigan. I exploit the walking distance cutoffs that determine transportation eligibility using a regression discontinuity design. I find that transportation eligibility increases attendance rates and lowers the probability of chronic absence. These effects are largest for economically disadvantaged students, who experience 0.5 to 1 percentage point increase in attendance rates and a 2 to 4 percentage point decrease in the probability of being chronically absent. These results are compelling evidence that school-provided transportation increases attendance for students most at-risk to miss school. However, I find no effect of school transportation on student achievement outcomes. Given the high costs of school transportation, targeting additional transportation services to chronically absent students as an attendance intervention may be more efficient than increasing bus services for all students.