In Chile, attendance is recognized as an important component of school quality and educational equity. The Chilean education system has clear, standardized definitions that apply country-wide, and a good registration system for school attendance that compiles national databases containing student-level, daily attendance, absences, and withdrawals for all children attending public schools. Moreover, these data are publicly available via open access, which allows the entire education community and the Ministry of Education access to all schools' data in an organized, centralized manner. These data contribute to ongoing scholarship about the impacts of attendance and absenteeism on education outcomes. In practice, schools use attendance data to monitor progress toward goals. The Ministry of Education uses data to calculate and pay school subsidies that are linked directly to average monthly attendance in accordance with Chilean law, and to classify schools into categories of education quality. Chilean Fundación Educacional Oportunidad uses attendance data and continuous quality improvement methods to promote attendance and prevent chronic absenteeism with more than 150 schools via a regional Learning Network. Meanwhile, the Learning Network fills an important gap by repurposing the nationally reported data to calculate and focus on individual-level attendance and by creating opportunities for practitioners to learn together how to promote attendance and prevent chronic absenteeism. This paper describes the context of Chile and its educational system; the definition, recording, reporting and use of attendance data; and the methods, outcomes and lessons learned by the regional Learning Network.