Millions of Americans of all ages face the challenge of living with serious illnesses such as advanced cancer, heart, or lung disease. Many people with serious illness are increasingly cared for in community settings. While the number of community-based programs to provide care for those with serious illness has grown significantly, the quality of care provided is not consistent across geographic locations or care settings. Care for the serious illness population often features gaps in coordination across sites of care and poor patient and family perceptions as to the quality of care provided. In an effort to better understand and facilitate discussions about the challenges and opportunities related to identifying and implementing quality measures for accountability purposes in community-based serious illness care, the National Academies of Sciences, Engineering, and Medicine held a public workshop on April 17, 2018, in Washington, DC. Workshop participants explored the current state of quality measurement for people with serious illness, their families, and caregivers, with the aim of identifying next steps toward effectively implementing measures to drive improvement in the quality of community-based care for those facing serious illness. This publication summarizes the presentations and discussions from the workshop.