This report examines the implementation and effects of the academic summer program for middle school students offered by Building Educated Leaders for Life (BELL). BELL's middle school program serves rising sixth- through eighth-grade students who are performing one to two years below grade level. The goals of the program are to increase student's literacy and math skills and to enhance their social development. To achieve these goals, BELL provides students with 6.5 hours of daily programming for approximately five weeks, five days per week. Several types of activities are provided: academic instruction in math and English Language Arts; social and academic enrichment activities; and field trips, guest speakers, and community service. BELL's contributions to summer learning began with its now well-established program for elementary school students. More recently, growing demand for programs serving older students has led BELL to expand into middle school. In this study, which is funded by the Edna McConnell Clark Foundation's Social Innovation Fund, the impact of BELL's middle school program was evaluated using a random assignment research design -- a lottery-like process used to assign eligible students either to a program group that was invited to participate in the BELL program or to a control group that was not. The study was conducted in summer 2012 in three school districts that were new partnerships for BELL. Due to various challenges related to student recruitment, the study's sample size is smaller than planned, and the margin of error around the impact findings is quite large. Even so, the results in this report can still be useful for generating suggestive or preliminary evidence about the potential effects of a full-day, academically oriented summer program model for middle school students. (author abstract)