Gary Goertz is a scholar of international conflict, conflict management, and peace. He is the author or co-author of 9 books and more than 50 articles and chapters on issues of international conflict and peace, institutions, and methodology. His publications in this area include Contexts of International Politics (1994, Cambridge), Explaining War and Peace (2007) and, with Paul Diehl, Territorial Changes and International Conflict (1992) and War and Peace in International Rivalry (2000).

A major focus of his research is the Causes of Peace project, which explores the rise of peace in the international system. One central area of activity is the theory of international institutions and norms, which was an important of part of his book Contexts of International Politics (1994, Cambridge), then expanded and developed in the book International Norms and Decisionmaking: A Punctuated Equilibrium Model (Rowman and Littlefield, 2004). He is also working on a book on the evolution of regional economic institutions and their involvement in conflict management. 

Goertz's other major research emphasis is methodology. His methodological works include Social Science Concepts: A User's Guide (2006, Princeton University Press), Politics, Gender, and Concepts: Theory and Methodology (2008, Cambridge University Press), and A Tale of Two Cultures: Qualitative and Quantitative Research in the Social Sciences (2012, Princeton University Press).