Sex differences in the predictors for hepatocellular carcinoma (HCC) development after direct-acting antiviral (DAA) therapy was investigated. DAA therapy was given to 1438 (663 male, 775 female) patients. Sex differences in the HCC development rate and the factors contributing to HCC development after DAA therapy were investigated. Male patients had a significantly higher cumulative HCC incidence (log-rank test, P =  .007). On multivariate analysis, the fibrosis-4 index (HR = 1.11; 95%CI, 1.042-1.202, P =  .002) and posttreatment α-fetoprotein (AFP) (HR = 1.11; 95%CI, 1.046-1.197, P  =  .001) were found to be independent factors that contributed to HCC development following DAA therapy in female patients, whereas only posttreatment AFP (HR  =  1.090; 95%CI, 1.024-1.160, P  = .007) was an independent factor in male patients. The optimal posttreatment AFP cut-off values were set based on receiver operating characteristic curve analyses. The optimal posttreatment AFP cut-off value was much higher in females (6.0 ng/mL) than in male (3.5 ng/mL) patients. In conclusion both in male and female patients, posttreatment AFP was an independent predictor of HCC development after DAA therapy. However, the cut-off values differed between the sexes. In male patients, HCC could be seen in patients with relatively low posttreatment AFP levels; more careful observation might be needed in such patients.