The influence that students with special educational needs may exert on the schooling outcomes of their siblings without special educational needs has been given minimal attention in published research. Hence, the authors bring forth a unique contribution by evaluating the within-family effects of being a child without special educational needs in a family with a sibling with special educational needs. To do so, the authors utilized quasi-experimental methods on a sample of siblings in the Philadelphia School District over 6 years of observations. Because individual student data can be linked to home address information as well as classroom, school, grade, and year identifiers, the authors identified children in the same household over time and subsequently employs multilevel fixed effects models to evaluate achievement and nonachievement schooling outcomes. The results indicate that having a sibling with special educational needs is positively related to standardized achievement compared with those children whose siblings do not have special educational needs. This supports a positive spillover hypothesis. On the other hand, nonsignificance permeates the effects on nonachievement schooling results, including attendance, truancy, tardiness, and behavior. (Contains 4 notes and 9 tables.)