Academic achievement disparities based on parental education are robust during the middle school years. The current study examined whether cross-class friendship (i.e., reciprocal relationships between peers with different levels of parental education) decrease class-based achievement differences during a developmental phase when friends are particularly important. Relying on a sample of 4,288 sixth grade students ( M = 12.03 years) from 26 ethnically diverse middle schools, multilevel analyses were conducted predicting seventh grade grade-point-average, standardized achievement test scores, and teacher-rated academic engagement. The associations between parental education and academic achievement were reduced when students had at least one cross-class friendship at sixth grade. The findings are discussed in terms of how socioeconomic diversity of school-based friendships can level the academic playing field.