20th Century
- Anglo-Aro war (1901–1902) - Nigeria
- British expedition to Tibet (1903–1904)
- World War I (1914–1918) - United Kingdom, France, Belgium, Serbia, Italy, Russia, United States vs Germany, Austria-Hungary, Bulgaria and Ottoman Empire
- Easter Rising (1916) - Ireland
- Allied intervention in the Russian Civil War (1918–1922)
- Third Anglo-Afghan War (1919)
- Anglo-Irish War (1919–1921)
- World War II (1939–1945) see Military history of the United Kingdom during World War II
- Air warfare of World War II
- Pacific War (1937–1945)
- Anglo-Iraqi War (1941)
- Palestine (1945–1948)
- Greek Civil War (1946–1947)
- Cold War (1946–1990)
- Malayan Emergency (1948–1960)
- Korean War (1950–1953)
- Mau Mau Uprising (1952–1960)
- Cyprus Emergency (1955–1959)
- Suez Crisis (1956)
- Brunei Revolt (1962)
- Dhofar Rebellion (1962–1975)
- Indonesia-Malaysia confrontation (1962–1966)
- Aden Emergency (1963–1967)
- Northern Ireland Troubles (1969-mid 1990s)
- Cod War Confrontation (1975–1976)
- Iranian Embassy Siege (1980)
- Falklands War (1982)
- Gulf War (1990–1991)
- Bosnian War (1992–1996)
- Operation Desert Fox (1998)
- Kosovo War (1999)
Read more about this topic: Military History Of The United Kingdom