Peers' parents with a certain educational status generate spillover effects on adolescents' education outcomes through several extrinsic channels. However, evidence on the intrinsic mechanisms driving these spillover effects remains limited. Exploiting the data from China Education Panel Survey (CEPS) and a quasi-random class assignment design, we examine how exposure to peers with college-educated parents influences adolescents' academic performance. Our findings indicate that such exposure significantly enhances adolescents' academic performance, with a noted partial mediation effect through their own educational aspirations. In addition, heterogeneous analysis indicates that girls, adolescents with less-educated parents, and adolescents in non-key schools are particularly susceptible to peers' parental education through this mediating influence. The results advocate for educational policies to facilitate social interactions between students and college-educated adults, such as through guest lectures and mentoring programs, which could improve the educational aspirations and outcomes of adolescents.