The results of the Peer/Performance Relationship Study build on previous research findings demonstrating relational significance of peer influences to academic performance during adolescence. Whereas family, teachers, and friends play a significant role in a student’s academic career, extant literature about the relational dynamics between peers and academic achievement remains scarce. This study evaluated social support and negative interchanges in relation to self-reported grades in reading, mathematics, social studies, and science. Additionally, students’ gender, race, and perception of a friend’s level of school interest were measured. The sample consisted of 321 participants in the 6th, 7th, and 8th grade from three medium-sized suburban, public middle schools in the Midwest. Social support and negative interchanges were measured by scales of the Network of Relationships Inventory. Academic performance was measured as a grade point average of the scores for the four academic subjects. Results support the hypothesis that adolescents’ relationships with peers influence academic performance. Specifically, the study’s outcome demonstrates that social support was significantly and positively related to academic performance. Negative interchanges were not significantly related to academic performance. A positive correlation was found between level of school interest and academic performance. Furthermore, gender differences were found among social support, negative interchanges, and academic performance. There were no statistical differences for race. Altogether, these results are consistent with previous research findings and provide evidence for the importance of adolescent friendships and their impact on academic performance.