UNCTAD Model Law on Competition (Model Law) has been developed by member States' representatives gathered in UNCTAD intergovernmental meetings to provide guidance on competition legislations, particularly for developing countries that are not familiar with this field, recognizing their interest to be able to take appropriate actions towards anticompetitive practices. The discussion on the Model Law in UNCTAD dates back to the 1970s, when only around 20 jurisdictions in the world had competition laws and authorities, and most were developed countries. This publication revisits the Model Law from different angles; the origin and history of the Model Law, as well as its negotiation are discussed. Testimonials from young competition authorities from developing countries share the relevance of the Model Law in the drafting of their own competition laws and refer to the implications of the Model Law to developing countries.