Abstract Background Accumulated evidence supports the existence of sex-associated differences in immune systems. Understanding the role of sex in immune-related adverse events (irAEs) is important for management of irAE in patients receiving immunotherapy. Methods We performed meta-analysis on published clinical study data and multivariable logistic regression on pharmacovigilance data and applied a propensity algorithm to The Cancer Genome Atlas omics data. We further validated our observations in 2 independent in-house cohorts of 179 and 767 cancer patients treated with immune checkpoint inhibitors. Results A meta-analysis using 13 clinical studies that reported on 1096 female patients (36.8%, 95% confidence interval [CI] = 35.0% to 38.5%) and 1886 male patients (63.2%, 95% CI = 61.5% to 65.0%) demonstrated no statistically significant irAE risk difference between the sexes (odds ratio [OR] = 1.19, 95% CI = 0.91 to 1.54, 2-sided P = .21). Multivariable logistic regression analysis of 12 225 patients from the Food and drug administration Adverse Event Reporting System (FAERS) and 10 979 patients from VigiBase showed no statistically significant difference in irAEs by sex. A propensity score algorithm used on multi-omics data for 6019 patients from The Cancer Genome Atlas found no statistically significant difference by sex for irAE-related factors or pathways. The retrospective analysis of 2 in-house patient cohorts validated these results (OR = 1.55, 95% CI = 0.98 to 2.47, false discovery rate = 0.13, for cohort 1; OR = 1.16, 95% CI = 0.86 to 1.57, false discovery rate = 0.39, for cohort 2). Conclusions We observed minimal sex-associated differences in irAEs among cancer patients who received immune checkpoint inhibitor therapy. It may be unnecessary to consider sex effects for irAE management in clinical practice.