The National Academies Roundtable on Quality Care for People with Serious Illness, National Cancer Policy Forum, and Forum on Aging, Disability and Independence hosted a workshop that examined opportunities to better support family caregiving for people with cancer or other serious illnesses. This workshop built upon previous work, including the 2016 consensus report Families Caring for an Aging America. This Proceedings of a Workshop summarizes the discussions held during the workshop, which focused on: strategies to better capture, understand, and act on family caregiver input and experience; research gaps and opportunities to guide caregiving for patients with serious illnesses; potential policy and practice opportunities to advance family-centered care for serious illness; and opportunities to embed a health equity focus across family caregiving research, policy, and practice.