Matthew Nimetz is an American diplomat and former lawyer, and one of the founders of the Center for Democracy and Reconciliation in Southeast Europe (CDRSEE) and the Joint History Project (JHP). A retired managing director of a global private equity firm, he served as the United Nations Special Representative for the naming dispute between Greece and the former Yugoslav Republic of Macedonia (now the Republic of North Macedonia). He also held the position of U.S. Under Secretary of State for Security Assistance, Science, and Technology, contributing significantly to international diplomacy and regional cooperation.