This tool is part of a series of technical assistance resources on financing and sustaining out-of-school time and community school initiative. These tools and resources are intended to assist policymakers, program developers and community leaders in developing financing and sustainability strategies to support effective initiatives. For nearly a decade, schools and communities nationwide have implemented comprehensive out-of-school time programming with grants from the U.S. Department of Education's 21st Century Community Learning Centers (21CCLC) program. The Finance Project interviewed former and current 21CCLC grantees and state 21CCLC administrators between July 2005 and March 2006 to learn about the challenges to sustainability and the keys to success. It became clear through these conversations that various factors both at the program level and in the administration of grants can help or hinder success with sustainability. This strategy brief presents the findings of the study and describes how both grantees and policymakers can promote the sustainability of 21CCLC programs. Sections of this report include: (1) Introduction; (2) Background; (3) Methodology; (4) Keys to Sustainability at the Program Level; (5) How Policymakers Can Encourage Sustainability; (6) Effects of NCLB on Sustainability; and (7) 21CCLC Policy: Looking Forward. Appendix I, Profiles of Successful Sustainability Strategies, presents: profiles of Columbine Elementary School; Claremont School District; and the North Carolina Northwest Three Afterschool Consortium. Appendix II presents: State-by-State Information on 21CCLC. The brief also contains additional resources on sustainability and select finance project resources. (Contains 11 footnotes.) [This tool is part of a series of resources developed with additional support from the Wallace Foundation.]