"The Forgotten War" (capitalized) most often refers to:

• Forgotten War (book), a 2013 book about the Australian frontier wars
• Korean War (in the United States)
• Ifni War (in Spain)

The term forgotten war is also sometimes, though much less commonly and less specifically, used to refer to:

• Southern theater of the American Revolutionary War
• Philippine–American War
• War of 1812 (outside of the United States)
• First Barbary War and Second Barbary War
• Campaigns in Finland during World War II (outside of Finland); see Military history of Finland during World War II
• Forest Brothers resistance in the Soviet-occupied Baltic states
• Laotian Civil War (outside of Laos)
• Burma Campaign (outside of Burma)
• Spanish Civil War (outside of Spain)
• Soviet–Afghan War
• First Chechen War and Second Chechen War (outside of Chechnya)
• War in Afghanistan (2001–2021) (outside of Afghanistan)
• War in Donbas (2014–2022) (outside of Ukraine)