Introduction: Frailty is a common condition in older adults, which consists in an increased vulnerability to stressors and a higher frequency of adverse outcomes, after this exposure. Objective: The objective of this study was to conduct a systematic review and meta-analysis on the prevalence of frailty in Mexican older adults and explain the causes of heterogeneity. Methods: Systematic review of the literature on the prevalence of frailty in Mexican older adults including gray literature. Metaanalysis with random effects was performed for all studies and subsequently stratified by potentially explanatory characteristics (type of tool, sample, sex of the participants, type of publication, age of the participants, etc.). Period prevalence, confidence intervals (CI), and heterogeneity are reported. Results: Of a total of 16 studies included with 18,965 older adults, the prevalenceof frailty was 31.2% (95% CI: 24.9-37.4%), with a heterogeneity of 98.7%. When classifying frailty with subjective tools, the lowest heterogeneity was obtained (78.8%), with a prevalence of 38.6% (95% CI: 35.9-41.3). Conclusion: The significant variability of the prevalence between the studies is increased by some individual characteristics included resulting in a variety of definitions, diagnostic tools, and interpretations in relation to the frailty of research.