This study investigated a Response to Intervention (RtI) practice at the middle school level using a randomly assigned Tier 2 vocabulary intervention. Although RtI research has documented improvement in the academic performance of elementary-aged students, RtI research in support of improved student performance in secondary schools is not prevalent. This study randomly assigned 86 sixth, seventh, and eighth graders into either the treatment or control condition. The purpose was to investigate whether middle school vocabulary instruction impacted vocabulary and/or comprehension growth for identified at-risk students. The experimental condition showed significant results for vocabulary (p=.011) but not comprehension (p=.657) on easyCBM outcome measures. Results are discussed in relation to teaching vocabulary independent of teaching comprehension directly.