Objective Internet gaming disorder (IGD) is a new disorder currently positioned in the appendix of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Few clinical studies report that psychological and pharmacological interventions can significantly reduce the severity of IGD symptomatology. The aim of this review was to assess current knowledge of the short‐ and long‐term benefits of IGD interventions. This review presents a systematic evaluation of definitions of diagnosis and treatment outcomes employed in IGD treatment studies, including an assessment of goodness of fit with the DSM‐5 classification. Method A computer database search of Academic Search Premier, PubMed, PsychINFO, ScienceDirect, Web of Science, and Google Scholar was conducted to identify all available research evidence on Internet gaming disorder treatment (N = 8 studies). Diagnostic and treatment outcome parameters were systematically evaluated. Results Several weaknesses of IGD treatment literature were identified. Only 2 treatment studies have employed an equivalent method of diagnosis for IGD. Studies have not assessed formative change in diagnostic status at posttreatment or follow‐up. Duration of follow‐up has been inadequate to assess relapse and remission. Posttreatment assessment has been predominantly limited to IGD symptomatology, comorbidity, and frequency of gaming behavior. Conclusion Currently, there is insufficient evidence to warrant suggestion that trialled IGD interventions confer a long‐term therapeutic benefit. Several improvements to study design and reporting are proposed to guide future studies of IGD.