The present investigation examined the benefits of pre-K through the end of kindergarten for children from low-income homes who lived in a large and diverse county (n = 2,581) as well as factors associated with a reduction in benefits during the kindergarten year. Results revealed that pre-K graduates outperformed nonattenders in the areas of achievement and executive functioning skills at the end of kindergarten, and also that the benefits of pre-K at the start of the year diminished by a little more than half. This convergence between groups' performance was largest for more constrained skills, such as letter-word identification, and was attributed to the fact that nonattenders made greater gains in kindergarten as compared with graduates of pre-K. Importantly, convergence in the groups' performance in kindergarten was not attributed to pre-K children's classroom experiences in kindergarten. Convergence was, however, attributable to preexisting individual differences, and there was support for the notion that even though children's skills are susceptible to improvement as a result of pre-K, their longer-term outcomes are likely to be impacted by factors that are outside the scope of early schooling.