Informed by the current literature, this study examines social contexts across middle grade schools with different grade span configurations. In doing so, the authors aim to build understanding of where and how to target interventions in the middle grades to enhance maintenance of social-emotional adjustment and experiences from middle childhood to early adolescence. Specifically, utilizing a large national dataset--the Early Childhood Longitudinal Study, Kindergarten Class of 1998-1999 (ECLS-K)--the authors: (1) describe the factor structure of the middle grade school social context as reported by administrators and teachers; (2) examine variation in social context among middle grade schools with different grade span configurations (k-8 schools; 6-8 middle schools; 7-9 junior high schools), controlling for school demographic and structural characteristics; and (3) test the role of middle grade school social context in the associations between school grade span configuration and student social adaptation and experiences (school attachment, perceived peer support, peer academic values). Results showed this study identified school social context as a potentially critical avenue of intervention toward supporting students' social and academic development in the middle grades. Tables and figures are appended.