This brief describes changes in the prevalence of and reasons for missed, canceled, and rescheduled appointments with military or civilian providers between 2013 and 2018. In 2015, TRICARE introduced an online feature that enables beneficiaries to set reminders via an automated telephone message, a text, and/or email for their appointments at military facilities (Military.com 2015). Differences over time in the prevalence and reasons for missed, canceled, and rescheduled appointments might mean that the reminder system is helping beneficiaries keep their appointments. We compare these data for direct care versus purchased care users.