Background/Context: The age at which children can enter kindergarten continues to be discussed in both educational research and practice, and the debate for whether to increase kindergarten entry age remains active on both sides. A critical oversight has been the lack of attention paid towards entry age for those students who begin school with a disability ("SWDs"). The lack of empirical evidence in this domain is highly concerning given that statewide policies and practices that affect the general schooling population will now also be affecting SWDs who are increasingly being educated in general education classrooms and schools and are hence subject to general educational policies and practices. Purpose/Objective/Research Question/Focus of the Study: Our study asked the following two research questions: 1. For children who begin kindergarten with a disability, does older versus younger entry age link to differences in short- and long-term achievement outcomes? 2. For children who begin kindergarten with a disability, does older versus younger entry age link to differences in short- and long-term socio-emotional measures? Population/Participants/Subjects: This study utilizes data from the newly released Early Childhood Longitudinal Study-Kindergarten Class of 1998-1999. Data were collected in several waves: the fall and spring of kindergarten (1998-99), in the spring of 1st grade (1999-00), the spring of 3rd grade (2002), the spring of 5th grade (2004), and the spring of 8th grade (2007). We analyzed data from the elementary school waves. Research Design: This study examined two sets of outcomes. First was reading and math achievement. The second set included socio-emotional scales based on both teacher ratings of child behavior. These outcomes were regressed on a measure for having attended kindergarten at an older entry age as well as a wide span of child and family characteristics. Error terms were clustered at the school level to account for nested data. Findings: The findings of the current study suggest there is little evidence that older kindergarten entry age links to differences in academic achievement for entrants with disabilities. However, older entrants with disabilities had much fewer instances of problem behaviors compared to those children with disabilities who began school at a younger age. Older entrants with disabilities also had higher social skills compared to entrants with disabilities who entered school at a younger age, though these findings were short-run, with little evidence extending beyond first grade. Conclusions/Recommendations: Later kindergarten entry may be one way to help SWDs ease the transition into schooling, given that prior research has found that kindergarten entry for SWDs can elevate stress and anxiety for this vulnerable group of students. Hence, SWDs might be especially benefitting greatly from an extra year of maturation before beginning formal schooling. Future research might examine what interventions and developmental services might be best at boosting SWDs' development during that additional time prior to school.