The present study examines an ecological model for intervention use to explain student vocabulary performance in a multi-tiered intervention setting. A teacher self-report measure composed of factors hypothesized to influence intervention use at multiple levels (i.e., individual, intervention, and system level) was administered to 54 teachers and 48 interventionists conducting vocabulary interventions with different levels of instructional intensity with 553 kindergarten students. The reliability and validity of the measure in the context of a specific multi-tiered intervention was explored. Of particular interest was the potential explanatory power of system-level factors, over and above intervention-specific measures of fidelity, to explain student performance in a multi-tiered context. Results indicate that the climate of the school system predicted student performance in the Tier 1 context, and intervention feasibility predicted student performance in Tier 2. However, the intervention-specific fidelity measure was not a significant predictor. This research provides supporting evidence for the use of ecological models of intervention implementation to capture factors that influence intervention use and performance in multi-tiered settings.