Gestalt therapy (GT) is a humanistic clinical approach. The research concerning the efficacy of this model represents a controversial and quite poorly investigated topic within the general field of psychotherapy effectiveness. An up-to-date review of the studies concerning GT efficacy is currently lacking. Therefore, we conducted a systematic review of all available studies in the past twelve years aiming to give an overview of the most important findings of empirical researches published in international peer review journals in English and Italian languages. A total of 11 studies were included in this review. GT intervention was shown to especially improve conduct in the group therapy setting—not only for clinical disorders, but also related to other social issues. Findings allow suggesting certain reflections concerning future directions in GT research.