In response to growing evidence that young people aging out of foster care face significant challenges during their transition to adulthood and fare more poorly than their peers across a wide range of life domains, the Fostering Connections to Success and Increasing Adoptions Act of 2008 gave states the option to extend eligibility for federally funded foster care to age 21. This change in policy meant that states would, for the first time, receive federal funding to support young people in foster care until their 21st birthday. Extended foster care has emerged as a key mechanism for providing young people in foster care with opportunities to prepare for their transition to adulthood by developing critical life skills, pursuing academic and career goals, and building social networks. Central to extended foster care are Independent Living Programs (ILPs) and Supervised Independent Living Placements (SILPs). ILPs provide services and resources that prepare young people for the transition to independent living. SILPs are living arrangements that provide a bridge between being in a foster care placement and living fully independently. This policy brief examines the critical and complementary roles that ILPs and SILPs can play in supporting young people in extended foster care. The authors begin by briefly summarizing what they know about the transition to adulthood for young people aging out of foster care, describing a conceptual framework for that transition, and identifying key federal legislation enacted over the past four decades. Next, they discuss extended foster care and the role that ILPs and SILPs can play in preparing young people in extended foster care for their transition to adulthood. Finally, the authors offer policy and practice recommendations.