Purpose: The purpose of this investigation was to conduct an evidence-based systematic review (EBSR) of peer-reviewed articles from the last 30 years about the effect of different service delivery models on speech-language intervention outcomes for elementary school-age students. Method: A computer search of electronic databases was conducted to identify studies that addressed any of 16 research questions. Structured review procedures were used to select and evaluate data-based studies that used experimental designs of the following types: randomized clinical trial, nonrandomized comparison study, and single-subject design study. Results: The EBSR revealed a total of 5 studies that met the review criteria and addressed questions of the effectiveness of pullout, classroom-based, and indirect-consultative service delivery models with elementary school-age children. Some evidence suggests that classroom-based direct services are at least as effective as pullout intervention for some intervention goals, and that highly trained speech-language pathology assistants, using manuals prepared by speech-language pathologists to guide intervention, can provide effective services for some children with language problems. Conclusion: Lacking adequate research-based evidence, clinicians must rely on reason-based practice and their own data until more data become available concerning which service delivery models are most effective. Recommendations are made for an expanded research agenda.