Although the Barcelona Clinic Liver Cancer staging system does not recommend radiation therapy (RT) as a locoregional modality in hepatocellular carcinoma (HCC), many prospective and retrospective studies have reported excellent local control with favorable survival rates after RT using modern techniques. Additionally, there have been several comparative or meta-analysis results reporting the superiority of RT in unresectable HCC. Therefore, it might be more reasonable to apply RT in unresectable HCC as an alternative locoregional modality to improve local control in HCC. However, several considerations for the application of RT in HCC exist. The considerations for RT in HCC are purpose, combination treatment and technique. The purpose of RT should be based on baseline liver status as well as tumor extent and location. There are several reasonable advantages in local, intrahepatic and extrahepatic control when combined with other modalities, but it could lead to overtreatment in some cases. The technical considerations according to the purpose and combination modality are the final step. For the application of RT in HCC, the purpose of RT, combination strategy and technical considerations should be taken into account.