Attendance in kindergarten and elementary school robustly predicts student outcomes. Despite this well-documented association, there is little experimental research on how to reduce absenteeism in the early grades. This paper presents results from a randomized field experiment in 10 school districts evaluating the impact of a low-cost, parent-focused intervention on student attendance in grades K-5. The intervention targeted commonly held parental misbeliefs undervaluing the importance of regular K-5 attendance as well as the number of school days their child had missed. The intervention decreased chronic absenteeism by 15%. This study presents the first experimental evidence on how to improve student attendance in grades K-5 at scale and has implications for increasing parental involvement in education.