The services of online games in Thailand are the business that have the high market value. However, there is no specific law applying with online games in Thailand resulting in the law problems such as the contract occurrence of online games, the problems related to the status and ownership of virtual properties, the problems using unfair contract terms, and the problems about liability of individuals party that related to online games. Therefore, this thesis studies and analyses to find legal measures applied to online game services by comparing laws in the United States and Korea. The matter of online game contract occurrence which are standard contracts in electronic form. Thai law does not specify any intention which leads to the contract occurrence. However, in US and Korean laws, the intention of a r standard contract that ready to be applied to the tender offer must allow recipients to review the contracts firstly (Opportunity to review rule). For the status and ownership of virtual properties in online games, virtual properties regard as the right for contracts of online game services which are valuable, and online game players can take their ownerships. Therefore, the virtual property is regarded as properties under the Civil and Commercial Code. The juristic act of trading virtual properties is regards as the transfer of claims. For unfair contractual terms, it is unclear in Thailand whether any contract is fair awith the discretion of court to decide the fairness in the contract. In Korea, there is the identification of the unfair contract nature. This ensures that any contract is enforceable. For civil liability of the individual behaviors from individual’s party that related to online games such as playing online games by using auto-play programs and abolishing online game services, the study shows that Thailand tort liability will cover only damages to legitimate rights which are dissimilar to the Korean and US tort laws providing the protection against all damages. In addition, Thailand has no specific law defining the liability for various behaviors of online game players like Korea. Nevertheless, Thailand civil liability law is still sufficient to address the liability of various parties in online games. The author suggests that the further revision be adopted the principle of Opportunity to review rule for consumer contract or standard contract in the civil and commercial codes and amendment of the unfair contract act by defining the unfair contract type explicitly to reduce the uncertainty of court discretion