The National Summer Learning Project, launched by the Wallace Foundation in 2011, includes an assessment of the effectiveness of voluntary, district-led summer learning programs offered at no cost to low-income, urban elementary students. The study, conducted by RAND, uses a randomized controlled trial and other analytic methods to assess the effects of district-led programs on academic achievement, social-emotional competencies, and behavior over the near and long term. All students in the study were in the third grade as of spring 2013 and enrolled in a public school in one of five urban districts: Boston; Dallas; Duval County, Florida; Pittsburgh; or Rochester, New York. The study follows these students from third to seventh grade; this report describes outcomes through fifth grade. The primary focus is on academic outcomes but students' social-emotional outcomes are also examined, as well as behavior and attendance during the school year. Among the key findings are that students with high attendance in one summer benefited in mathematics and that these benefits persisted through the following spring; students with high attendance in the second summer benefited in mathematics and language arts and in terms of social-emotional outcomes; and that high levels of academic time on task led to benefits that persisted in both mathematics and language arts. Key Findings: (1) Implementation Findings: Programs implemented common features with fidelity but instructional quality varied within and across sites; (2) Causal Findings on Program Effects: (a) Summer programs produced a modest near-term benefit in mathematics that dissipated by the next fall; (b) There was no causal evidence that the programs produced benefits in language arts, social emotional outcomes, or student attendance or grades during the school year; and (c) There was no causal evidence that offering two summers of programming provided benefits; (3) Correlational Findings on Program Effects: (a) There is promising evidence that students with high attendance in one summer benefited in mathematics and that these benefits persisted through the following spring; (b) There is promising evidence that students with high attendance in the second summer benefited in mathematics and language arts and that these effects persisted; (c) There is promising evidence that students with high attendance in the second summer benefited in terms of social-emotional outcomes; (d) There is promising evidence that students with high levels of academic time on task benefited from the programs and that these benefits persisted in both mathematics and language arts; and (e) There is promising evidence that students who received high-quality language arts instruction benefited from the programs. [For the appendixes to this report "Learning from Summer: Online Technical Appendixes," see ED605494.]