Background <p>Problematic smartphone use (PSU) has been increasingly linked to depression, but evidence on whether this association differs by gender remains inconsistent. This review synthesizes the existing evidence on gender differences in the PSU–depression association.</p> Methods <p>Four academic databases (PubMed, Web of Science, Scopus, ProQuest) and one academic search engine (Google Scholar) were searched, with the original search conducted through September 2024 and an updated search completed in May 2026. The review was prospectively registered on the Open Science Framework and followed the PRISMA guidelines. Eligible studies examined gender differences in the association between PSU and depression. Quality was assessed using the Mixed Methods Appraisal Tool (MMAT).</p> Results <p>Of the 16 included studies, 13 were cross-sectional and three longitudinal. Fifteen studies statistically tested and found a positive PSU–depression association. Gender patterns were divided: five studies found the association stronger in females, five found it stronger in males, and six found no significant gender difference in the qualitative synthesis. One longitudinal study provided direct evidence of bidirectionality.</p> Conclusion <p>Findings on gender differences in the PSU–depression association are far from uniform, with comparable numbers of studies supporting female vulnerability, male vulnerability, and no difference. Observed gender patterns likely reflect moderating factors including usage type, age group, cultural context, and measurement heterogeneity rather than a fundamental difference in vulnerability between men and women. The predominance of cross-sectional designs and reliance on self-report instruments limit causal inference, and longitudinal and mechanistic research is needed to clarify the underlying associations.</p> OSF registration <p><a href="https://doi.org/10.17605/OSF.IO/E5SGN">https://doi.org/10.17605/OSF.IO/E5SGN</a></p>