© 2018 International Society for Sexual Medicine. Background: Sexual dysfunction is a common problem among men and women and is associated with negative individual functioning, relationship difficulties, and lower quality of life. Aim: To determine the magnitude of associations between 6 health-related lifestyle factors (cigarette smoking, alcohol intake, physical activity, diet, caffeine, and cannabis use) and 3 common sexual dysfunctions (erectile dysfunction, premature ejaculation, and female sexual dysfunction). Methods: A comprehensive literature search of 10 electronic databases identified 89 studies that met the inclusion criteria (452 effect sizes; N = 348,865). Pooled mean effects (for univariate, age-adjusted, and multivariable-adjusted estimates) were computed using inverse-variance weighted random-effects meta-analysis and moderation by study and population characteristics were tested using random-effects meta-regression. Results: Mean effect sizes from 92 separate meta-analyses provided evidence that health-related lifestyle factors are important for sexual dysfunction. Cigarette smoking (past and current), alcohol intake, and physical activity had dose-dependent associations with erectile dysfunction. Risk of erectile dysfunction increased with greater cigarette smoking and decreased with greater physical activity. Alcohol had a curvilinear association such that moderate intake was associated with a lower risk of erectile dysfunction. Participation in physical activity was associated with a lower risk of female sexual dysfunction. There was some evidence that a healthy diet was related to a lower risk of erectile dysfunction and female sexual dysfunction, and caffeine intake was unrelated to erectile dysfunction. Publication bias appeared minimal and findings were similar for clinical and non-clinical samples. Clinical Translation: Modification of lifestyle factors would appear to be a useful low-risk approach to decreasing the risk of erectile dysfunction and female sexual dysfunction. Strengths and Limitations: Strengths include the testing of age-adjusted and multivariable-adjusted models and tests of potential moderators using meta-regression. Limitations include low statistical power in models testing diet, caffeine, and cannabis use as risk factors. Conclusion: Results provide compelling evidence that cigarette smoking, alcohol, and physical activity are important for sexual dysfunction. Insufficient research was available to draw conclusions regarding risk factors for premature ejaculation or for cannabis use as a risk factor. These findings should be of interest to clinicians treating men and women with complaints relating to symptoms of sexual dysfunction. Allen MS, Walter EE. Health-Related Lifestyle Factors and Sexual Dysfunction: A Meta-Analysis of Population-Based Research. J Sex Med 2018;XX:XXX-XXX.