A Defense pact is a type of treaty or military alliance where the signatories promise to support each other militarily, to defend each other. In general the signatories point out the threats in the treaty and concretely prepare to respond to it together.
- 1992 – Collective Security Treaty - established Collective Security Treaty Organisation including Armenia, Belarus, Kazakhstan, Kyrgyzstan, and Tajikistan.
- 2010 - The Agreement on Strategic Partnership and Mutual Support between Azerbaijan and Turkey for strategic partnership and security co-operation.
- 1947 – Inter-American Treaty of Reciprocal Assistance (Rio Treaty) – Western Hemisphere mutual defense.
- 1949 – North Atlantic Treaty (Treaty of Washington) – establishes NATO mutual defense organization.
- 1951 – Mutual Defense Treaty (U.S.–Philippines) – between the Philippines and the United States.
- 1951 – ANZUS – mutual defense alliance between Australia, New Zealand, and the United States.
- 1951 – Security Treaty Between the United States and Japan – bilateral treaty between Japan and the United States.
- 1953 – Mutual Defense Treaty Between the United States and the Republic of Korea – Created an alliance with South Korea.
- 1954-1977 – Southeast Asia Treaty Organization – between Australia, France, New Zealand, the Philippines, Thailand, Pakistan, the United Kingdom and the United States.
- 1960 – Treaty of Mutual Cooperation and Security between the United States and Japan – mutual defense treaty with Japan.
- 1955 – Warsaw Pact – between Albania, Bulgaria, Czechoslovakia, East Germany, Hungary, Poland, Romania and Russia.
- 1881 – Dreikaiserbund – between Germany, Austro-Hungarian Empire, and Russia.
- Volker Krause, J. David Singer "Minor Powers, Alliances, And Armed Conflict: Some Preliminary Patterns", in "Small States and Alliances", 2001, pp 15-23, ISBN 978-3-7908-2492-6 (Print) ISBN 978-3-662-13000-1 (Online)
- Fulvio Attinà "State aggregation in defense pacts: systemic explanations", Jean Monnet Working Papers, University of Catania, nr. 56, November 2004, ISSN 2281-9029