This study aims to find out how the influence of the End Child Prostitution, Child Pornography, And Trafficking Of Children For Sexual Purposes or ECPAT. ECPAT is a non-governmental international organization that give their influences to Thai government’s policy making in handling of child sex tourism cases as a form of international crime. The author used the content analysis method as collecting the required information by looking for references related to the cases discussed through books and internet. The type of data used is secondary data type with various literature as data source. The author uses Trans-national Advocacy Networks theory in this research. The results of this research indicate that the development of child sex tourism in Thailand is the result of weak child protection laws in that country and the lack of law enforcement. The tourism industry in Thailand is the main pillar of the economy so that the role of ECPAT as an organization that has an international network capable of influencing Thai government policy making in 2011 where the Thai government renewed the National Plan of Action to protect children from more global commercial sex crimes.