This practitioner brief is one of a series highlighting concrete strategies that education leaders can use to increase equity in education by building learning environments that meet all students' social and emotional needs. This brief discusses how school districts can use partnerships with outside organizations and agencies to help provide additional services. It discusses the evidence on whether partnerships can effectively promote students' social and emotional well-being and their academic success. It further reflects on how districts and schools can expand these partnerships to assist school transformation at three levels--the structural and policy level, the staff level, and the program level--while weaving in practical advice from district leaders with successful district-wide partnership systems. [For the companion report "School-Community Partnerships. Solutions for Educational Equity through Social and Emotional Well-Being. Voices from the Field," see ED616541.]