A one-group repeated-treatment design was used to examine the academic year and summer oral reading fluency outcomes for students attending a district-sponsored summer literacy program (N = 250). Piecewise growth models applied to longitudinal data obtained during the first and second grade and over the course of the intervening summer revealed that oral reading fluency increased during each period of schooling, with the most rapid increase occurring during the intensive summer school intervention period. The gains in reading fluency observed during periods of schooling contrasted with periods of stagnation or loss when students were not in school during each of two summer breaks. The observed pattern of learning suggests that for the struggling readers we studied, schooling "mattered" regardless of when in the calendar year it was experienced. Challenges and opportunities associated with evaluating summer program performance are discussed.