Backgrounds <p>Overactive bladder (OAB) is a common urological disorder with an incompletely understood pathogenesis that markedly impacts patients’ quality of life, and hepatitis C virus (HCV) infection is associated with systemic inflammation and extrahepatic complications, with their potential association remaining understudied. This study thus aims to investigate the association between HCV and OAB in adults. This study aims to investigate the association between hepatitis C virus (HCV) and overactive bladder (OAB) in adults.</p> Methods <p>This study analyzed data from the National Health and Nutrition Examination Survey (NHANES) conducted between 2013 and 2018. Logistic regression analysis, subgroup analysis, and interaction tests were employed to assess the association between HCV and OAB. Additionally, propensity score matching (PSM), inverse probability weighting (IPTW), and overlap weighting (OW) were employed to control for confounding factors. E-value analysis was conducted to assess the robustness of results against unmeasured confounders, while sensitivity and specificity analyses evaluated the predictive performance of HCV for OAB.</p> Results <p>This study included 14,012 patients aged ≥ 20 years. Logistic regression analysis demonstrated an association between HCV and OAB (OR = 2.06, 95% CI 1.46–2.90, <i>p</i> &lt; 0.001). Subgroup analyses and interaction tests confirmed that the relationship between HCV and OAB remained consistent across all subgroups (all interaction P values &gt; 0.05). After PSM, IPTW, and OW analyses, the association between the two remained significant; E-value analysis demonstrated strong robustness to unmeasured confounders; Sensitivity and specificity results indicate that HCV has predictive value for OAB.</p> Conclusions <p>The findings of this study indicate that there is a significant correlation between HCV and OAB.</p>