Even though the general concept of child protection has long been existing for almost a century, it must be accepted that the concept of child protection from which fact-finding must be conducted upon such children and juveniles in the criminal justice system is relatively new. Nowadays, it is indeed undeniable that fact-finding procedures conducted on children, or the so-called ùchild interviewû in the criminal justice system, has inter alia become one of international law topics to which priorities have been given at both regional and international levels. This article is aimed at reiterating the evolution of international legislation related to fact-finding from children and juveniles in the criminal justice system as appeared in provisions of various international legal instruments. This is so that such a fundamental universal concept and principle on this matter will be laid out as a foundation for the development of the most effective and child-sensitive fact-finding methods for children and juveniles, which can then be further applied and implemented in the Thai criminal justice system