Category:20th-century military alliances

• Collective Security Treaty Organization‎ (1 C, 5 P)

• NATO‎ (23 C, 50 P)

• Regional Security System‎ (1 C, 4 P)

• Warlord cliques in Republican China‎ (6 C, 17 P)
• Warsaw Pact‎ (3 C, 27 P)
• Western European Union‎ (1 C, 10 P)
• Western Union (alliance)‎ (2 C, 8 P)

The following 72 pages are in this category, out of 72 total. This list may not reflect recent changes.

• Agreement on Friendship and Cooperation between Bosnia and Herzegovina and Croatia
• Allies of World War I
• Allies of World War II
• Anglo-Egyptian treaty of 1936
• Anglo-Iraqi Treaty of 1930
• Anglo-Japanese Alliance
• Anglo-Polish alliance
• Anglo-Russian Convention
• Anglo-Soviet Agreement
• Anti-Comintern Pact
• ANZUK
• ANZUS
• Axis powers

• Balkan League
• Balkan Pact
• Balkan Pact (1953)
• Baltic Entente
• Treaty of Bucharest (1916)
• Bulgaria–Germany treaty (1915)
• Bulgarian–Ottoman convention (1915)

• Central Treaty Organization
• Confédération Interalliée des Sous-Officiers de Réserve
• Coalition of the Gulf War
• Collective Security Treaty Organization

• Treaty of Dunkirk

• Economic Community of West African States Monitoring Group
• Eight-Nation Alliance
• Entente Cordiale

• Finnish–Estonian defence cooperation
• Five Power Defence Arrangements
• Franco-Polish alliance
• Franco-Russian Alliance

• Georgian–Polish alliance

• Inter-American Treaty of Reciprocal Assistance

• Japan–Russia Secret Agreements
• Joint Defence and Economic Co-operation Treaty

• Latin Bloc (proposed alliance)
• Little Entente

• Major non-NATO ally
• Mutual Defense Treaty (United States–Philippines)
• Mutual Defense Treaty (United States–South Korea)

• NATO
• Nuclear umbrella

• Ogdensburg Agreement
• Ottoman–Bulgarian alliance
• German–Ottoman alliance

• Pact of Steel
• Peninsula Shield Force
• Polish–Romanian alliance

• Security Treaty between the United States and Japan
• Senegambia Confederation
• Sikorski–Mayski agreement
• Simonstown Agreement
• China–Germany relations (1912–1949)
• Southeast Asia Treaty Organization
• Split Agreement
• Starobilsk agreement

• Thanat–Rusk communiqué
• Treaty establishing the European Defence Community
• Treaty of Björkö
• Treaty of Brussels
• Treaty of Mutual Cooperation and Security between the United States and Japan
• Treaty of Sofia
• Tripartite Pact
• Triple Alliance (1882)
• Triple Entente

• U.S.–Japan Alliance

• Visegrád Group

• Warsaw Pact
• Western Union (alliance)