This umbrella review aimed to evaluate the evidence behind the Willems method for dental age estimation and detect methodological limitations in the existing systematic reviews. The study followed the Preferred Reporting Items for Overviews of Reviews (PRIOR), with the protocol registered in PROSPERO (CRD42023487745). Seven databases, including grey literature sources, were searched (Medline/PubMed, Scopus, LILACS, SciELO, Web of Science, Open Grey and Open Access Theses and Dissertations). Systematic reviews of cross-sectional studies on the Willems method were included. Two calibrated reviewers independently conducted study selection, data extraction, quality assessment (AMSTAR-2) and risk of bias (ROBIS). Five systematic reviews published between 2017 and 2022 were included. Combined sample sizes ranged from 9347 to 17,741 individuals aged 2.2 to 18 years. Meta-analyses reported minor overestimations in dental age, with differences varying by sex and ethnicity. However, significant methodological shortcomings were identified, such as lack of protocol registration, limited search strategies, and inadequate assessment of the risk of bias. All systematic reviews were rated as critically low quality and with a high risk of bias. The Willems method was deemed appropriate for dental age estimation by most studies, but methodological limitations of existing systematic reviews underscore the need for more rigorous research and improved standards.