This study examines the effects of an incentivized summer enrollment initiative on student persistence. In particular, we analyze how participation in summer classes (at least 3 credit hours) affect students' likelihood to reenroll in the fall semester at a two-year, private, technical college in Boston. The novel initiative, which provides eligible students with a free summer class of up to four credits, was launched in academic year 2010-2011. We obtained data for five consecutive cohorts since implementation at the Benjamin Franklin Institute of Technology. To study its effects, we build on the framework of academic momentum, human capital theory, and draw from the behavioral economics literature. To better account for potential selection bias in the estimation, this study employs two propensity score matching techniques, including a doubly robust design. We find that attending summer classes is associated with significant increases in students' chances to persist and reenroll in the fall semester. More specifically, we estimate the average treatment effect (ATE) and average treatment effect on the treated (ATET) to be between 30 and 32%. Results also show a higher percentage of students enrolling in summer classes at this institution (35%) when compared to national rates. Based on our results and previous findings in the literature, we argue there is mounting evidence that attending summer session increases student persistence and degree completion, and that the combination of summer enrollment with well-designed incentive structures can enhance positive effects further. Implications for policy and educational practice are discussed.