Supervision is a distinct competency area in professional psychology with a burgeoning research base. Yet it remains unclear to what extent the broad supervision research base generalizes specifically to supervision of psychological services in schools for both preservice trainees and credentialed school psychologists. The purposes of this study were to map and review current evidence regarding supervision in school psychology; consider the evidence in the context of the broader psychology supervision literature; and reflect on next steps for training, practice, and research of supervision in school psychology. A systematic review across school psychology journals and psychological supervision journals found only 37 peer refereed articles (21 empirical and 16 conceptual) published on the topic of supervision in school psychology since the year 2000. The topical coverage of these articles is summarized, including its contributions and limitations. Implications are drawn for future research of supervision in school psychology.