We investigated the impacts of a peer-facilitated instructional intervention in mathematics on progress towards readiness for college among 10th graders who facilitated instruction for 9th graders in algebra classrooms in urban secondary schools. A goal of the intervention is to promote readiness for college by placing middle-performing students in the role of instructional facilitators. The program draws on theory that holds that instructional facilitation helps facilitators enhance their content knowledge and develop in metacognitive and social-emotional domains. We used propensity score matching to evaluate the program's impact on facilitators' achievement of outcomes that represent early high school "on-track for college" benchmarks, benchmarks for college readiness, and college entry without need for remediation. Acting as a 10th grade instructional facilitator increased students' likelihood of meeting near-term, intermediate, and long-term indicators of college readiness. These results indicate that intensive long-term interventions in early high school that draw on students as resources can having lasting impacts on real-world metrics for college-readiness.