Fluent oral reading is an essential literacy skill, and data suggest that it is a consistent and persistent problem for many elementary school children. Peer-mediated instruction in which students work together to support each other is an evidence-based practice for improving performance in a variety of academic areas. In this study, we investigated the effectiveness of a peer-mediated fluency-building intervention for struggling readers in second grade. The intervention was provided to small groups of students referred to as difficult-to-remediate, treatment resisters, nonresponders, or lower responders in similar research. Oral reading fluency performance for students who received supplemental intervention (n = 17) was statistically significantly better than that for their peers who received only typical classroom instruction (n = 17). The effects of enhanced fluency instruction were evident across multiple benchmarks, and significant relationships were evident between oral reading fluency and comprehension. The authors discuss the findings in the context of similar peer-mediated interventions and the emerging development of targeted interventions to support response-to-intervention practices. (Contains 3 figures and 3 tables.)