With the development of transnational constitutionalism, constitutionalization of international law and internationalization of constitutional law become evident as a global trend. This trend is reflected in the recent internationalization of international human rights laws in Taiwan. Aside from governments, nongovernmental organizations (NGO) have played crucial roles in this process. This Article observes the roles that domestic NGOs have played in the ratification or internationalization of the Convention on the Elimination of Discrimination against Women (CEDAW), Convention on the Rights of Child (CRC), and the Framework Convention on Tobacco Control (FCTC). It finds that domestic NGOs have played double roles. Externally, these domestic NGOs actively demand the government to accede to international human rights regimes. Internally, they have led the process of internalization by promoting new legislation or implementation statutes. More importantly, this Article finds that globalization and technology advancement have provided NGOs with greater advantage in transnational networking and information, even way ahead the government. If leveraging properly, these domestic NGOs will become crucial players in the development of transnational constitutionalism encompassing both international and domestic laws.