Objective <p>The objective of this meta-analysis is to provide a comprehensive and up-to-date assessment of the prevalence of endometriosis and adenomyosis, addressing the limitations of existing research data and evaluating the quality of the data.</p> Methods <p>Adhering to the PRISMA 2020 guidelines, this study systematically searched the Web of Science, PubMed, Embase, and Google Scholar databases from their inception until January 2025 for studies related to adenomyosis and endometriosis. All studies that specifically reported the prevalence of adenomyosis and endometriosis, or provided data enabling calculation of their prevalence, were included. The research examined the occurrence of different subtypes of adenomyosis and endometriosis, as well as frequency in various populations. Furthermore, subgroup analyses were conducted to synthesize findings related to distinct diagnostic criteria, gynecological symptoms, and the prevalence of these two conditions across diverse populations. Meta-analyses were performed using <i>meta</i> software packages, and random-effects models with 95% confidence intervals (CI) were employed to determine the combined prevalence of adenomyosis.</p> Results <p>A total of 198,925,726 women from 127 studies (59 on adenomyosis and 68 on endometriosis) were included in this meta-analysis. The prevalence of focal and diffuse adenomyosis was found to be 17% (95%CI, 7%-30%) and 15% (95%CI, 9%-23%), respectively. The prevalence of peritoneal endometriosis, ovarian endometriosis, and deep endometriosis was recorded at 6% (95%CI, 1%-15%), 13% (95%CI, 5%-24%), and 10% (95%CI, 2%-24%), respectively. The prevalence of adenomyosis and endometriosis among women experiencing infertility was 31% (95%CI, 10%-58%) and 38% (95%CI, 25%-51%), respectively. Furthermore, among patients experiencing gynecologic symptoms, the pooled of adenomyosis and endometriosis was 41%-49%, and 18%-42%, respectively. The global prevalence of adenomyosis and endometriosis in the general population worldwide is 1% (95%CI, 0%-2%), and 5% (95%CI, 2%-9%), respectively.</p> Conclusions <p>In conclusion, endometriosis occurs more frequently than adenomyosis across various populations. Notably, it affects nearly 50% of individuals experiencing gynecological symptoms. This study provides valuables support for public health management and emphasizes the importance of prompt intervention and treatment for related conditions.</p>