Over one hundred and twenty countries across the world have already adopted or are in the process of adopting antitrust legislation. Laws designed to protect competition exist in every industrialized country of the Organization for Economic Cooperation and Development (OECD). The Canadian antitrust law of 1889 and the Sherman Act of 1890 in the United States were the first national laws that prohibited agreements restricting competition and efforts to create monopolies through unlawful methods.

Beginning in the mid-Eighties, laws on protecting competition have been adopted by numerous developing countries, Central and Eastern European countries and former Soviet republics, which are undergoing transitions to market economies. In 2007, antitrust laws similar to the Community model were also passed in the Peoples Republic of China. International organizations (OECD, World Bank, UNCTAD) offer advisory assistance for developing countries that are striving to introduce new laws to their legal systems to protect market functioning.

The laws on protecting competition are not the same in every country, especially in terms of institutional aspects and procedures. Within the European Union these laws have recently exhibited higher degrees of convergence as numerous countries have modified their national legislation on competition-related issues to bring them into alignment with Community law.

This increasing convergence of competition laws and application methods is also being witnessed in other industrialized countries across the world, though certain differences persist in the substance and procedures of legal profiles and specific competition-related policies.

In October 2001, the International Competition Networkwas launched to promote greater convergence across national regimes and broader and more effective cooperation between different authorities charged with the protection of competition. This initiative welcomed the participation of competition authorities from every country with national-level antitrust regulations. One hundred and four competition protecting authorities representing ninety-two different jurisdictions have joined the initiative so far.

Lastly there are the international cooperation agreements on antitrust matters (between the European Union and the United States, for example, and between the European Union and Canada). These are intended to promote cooperation and informational exchanges and to coordinate the Antitrust Authority's competition-related investigatory activities when multiple jurisdictions are involved in identifying and effectively sanctioning agreements restricting competition.