An increasingly prevalent family constellation is a home headed by a grandparent who is raising grandchildren. We explore the state of our knowledge about such grandparents with particular attention to its implications for service providers and researchers. In our review we address several key areas: (a) the costs and benefits of raising a grandchild; (b) the heterogeneity of custodial grandparent caregivers; (c) the critical need for social support among custodial grandparents; (d) parenting practices and attitudes among grandparents raising grandchildren; and (e) helping efforts at multiple levels with custodial grandparents. We also discuss directions for research and practice concerning custodial grandparents.