Much is known about the role of vocabulary in reading and the instructional procedures that improve vocabulary. Relatively less is known about feasible approaches to implement vocabulary interventions for struggling readers within tiered frameworks. The current study randomly assigned at-risk kindergarten and first-grade students to a vocabulary intervention that was implemented by noneducator AmeriCorps interventionists from local school communities. Analyses showed that kindergarten students assigned to intervention showed significantly greater improvement on a researcher-developed measure of vocabulary knowledge but not on a distal vocabulary measure. Significant findings were not observed within first grade. Results are discussed in terms of implications and future research for vocabulary interventions within tiered frameworks.