A war poet is a poet in time of and on the subject of war. The term, which is applied especially to those in military service during World War I, was documented as early as 1848 in reference to German revolutionary poet, Georg Herwegh.
World War I
For the first time, a substantial number of important British poets were soldiers, writing about their experiences of war. A number of them died on the battlefield, most famously Edward Thomas, Isaac Rosenberg, Wilfred Owen, and Charles Sorley. Others including Robert Graves, Ivor Gurney and Siegfried Sassoon survived but were scarred by their experiences, and this was reflected in their poetry. Robert H. Ross characterised the English "war poets" as a subgroup of the Georgian Poetry writers.
Many poems by British war poets were published in newspapers and then collected into anthologies. Several of these early anthologies were published during the war and were very popular, though the tone of the poetry changed as the war progressed. One of the wartime anthologies was The Muse in Arms, published in 1917. Several anthologies were also published in the years after the war had ended.
In November 1985, a slate memorial was unveiled in Poet's Corner commemorating 16 poets of the Great War: Richard Aldington, Laurence Binyon, Edmund Blunden, Rupert Brooke, Wilfrid Gibson, Robert Graves, Julian Grenfell, Ivor Gurney, David Jones, Robert Nichols, Wilfred Owen, Herbert Read, Isaac Rosenberg, Siegfried Sassoon, Charles Sorley and Edward Thomas.
In other countries
Canadian war poets of this period included John McCrae, who wrote In Flanders Fields, and Robert W. Service who worked as an ambulance driver for the Canadian Red Cross and was a war correspondent for the Canadian government.
Russia also produced a number of significant war poets including Nikolay Gumilyov (whose war poems were assembled in the collection The Quiver (1916)), Alexander Blok, Ilya Ehrenburg (who published war poems in his book "On the Eve"), and Nikolay Semenovich Tikhonov (who published the book Orda (The horde) in 1922).
The Spanish Civil War
The Spanish Civil War produced a substantial volume of poetry in English (as well as in Spanish). There were English-speaking poets serving in the Spanish Civil War on both sides. Among those fighting with the Republicans as volunteers in the International Brigades were Clive Branson, John Cornford, Charles Donnelly, Alex McDade and Tom Wintringham. On the Nationalist side, the most famous English language poet of the Spanish Civil War remains South African bard Roy Campbell.
World War II
By World War II the role of "war poet" was so well-established in the public mind that "Where are the war poets?" became a topic of discussion.. Robert Graves gave a radio talk 'Why has this War produced no War Poets?' in October 1941 and Stephen Spender also addressed the question at about the same time (as did T. S. Eliot a year later). Alun Lewis and Keith Douglas are the standard critical choices amongst British war poets of this time. In 1942, Henry Reed published a collection of three poems about British infantry training entitled Lessons of the War; three more were added after the war.
The American poet Karl Shapiro made a reputation based on poetry that he wrote during the war and published in his debut book of verse, V-Letter and Other Poems (1945). His book won the Pulitzer Prize that same year. Also, while serving in the U.S. Army, the American poet Randall Jarrell published his second book of poems, Little Friend, Little Friend (1945) based on his wartime experiences. The book includes one of Jarrell's best known war poems, "The Death of the Ball Turret Gunner." In his follow-up book, Losses (1948), he also focused on the war. The poet Robert Lowell stated publicly that he thought Jarrell had written "the best poetry in English about the Second World War."
Later American war poets
The Vietnam war produced a number of war poets, including Michael Casey whose début collection, Obscenities, drew on his work as military police officer in Vietnam's Quang Nga province. The book won the 1972 Yale Younger Poets Award. Other prominent Vietnam War poets include W. D. Ehrhart, Yusef Komunyakaa, and Bruce Weigl.
Most recently, the Iraq War has produced some notable war poets including Brian Turner whose début collection, Here, Bullet, is based on his experience as an infantry team leader with the 3rd Stryker Brigade Combat Team from November 2003 until November 2004 in Iraq. The book won numerous awards including the 2005 Beatrice Hawley Award, the 2006 Maine Literary Award in Poetry, and the 2006 Northern California Book Award in Poetry. The book also was an Editor's Choice in The New York Times and received significant attention from the press including reviews and notices on NPR and in The New Yorker, The Global and Mail, and the Library Journal. In The New Yorker, Dana Goodyear wrote that, "As a war poet, [Brian Turner] sidesteps the classic distinction between romance and irony, opting instead for the surreal." 
- "war poet noun" The Oxford Dictionary of English (revised edition). Ed. Catherine Soanes and Angus Stevenson. Oxford University Press, 2005
- Herwegh, Georg, The Columbia Encyclopedia (2008)
- The Times, Southern Germany, 29 September 1848
- Richard Perceval Graves, ‘Graves, Robert von Ranke (1895–1985)’, Oxford Dictionary of National Biography, Oxford University Press, 2004
- The Georgian Revolt, p.166.
- Westminster Abbey: Poets of the First World War
- R.R. Milner-Gulland in A.K. Thorlby (ed.), The Penguin Companion to Literature: European (Penguin, 1969), p. 762.
- The Penguin Book of Spanish Civil War Verse, edited by Valentine Cunningham (Penguin, 1980); see also War Poets Association: Spanish War
- Poems from Spain: British and Irish International Brigaders of the Spanish Civil War in Verse, edited by Jim Jump. (London: Lawrence & Wishart, 2006)
- Press, John (1 March 1994). "Poets of World War II". In Scott-Kilvert, Ian. British Writers: 007. New York: Charles Scribner's Sons. pp. 422–423. ISBN 978-0684166384. Retrieved 25 May 2015.
- Gilroy, Harry. "Poets Honor Memory of Jarrell at Yale." The New York Times 1 March 1966.
- W. D. Ehrhart, The Madness of It All: Essays in War, Literature and American Life, (Jefferson, NC: McFarland & Company, 2002) pp. 141-172.
- Unaccustomed Mercy: Soldier-Poets of the Vietnam War, edited by W. D. Ehrhart. (Lubbock, Texas: Texas Tech University Press, 1989)
- Lorraine Ash, A Poet Goes to War, September 17, 2006
- Book Publisher's Site Info on Book
- New Yorker Article
- Silkin, Jon. Out of Battle: The Poetry of the Great War. Basingstoke: Palgrave Macmillan, 1972. Rpt. 1998. ISBN 978-0-312-21404-3.
- Roy, Pinaki. The Scarlet Critique: A Critical Anthology of War Poetry. New Delhi: Sarup Book Publishers Pvt. Ltd., 2010. ISBN 978-81-7625-991-0.
- The Poetry of the Boer War
- War Poems From Iraq
- War Poets Association
- The First World War Poetry Digital Archive
- The pro-war 1917 pamphlet Pro Patria (1917) by Philadelphia poet Florence Earle Coates (1850–1927)
- Echenberg Collection of over 5000 volumes of War Poetry
- Roy, Pinaki. Wilfred Owen: The Man, the Soldier, the Poet. Kolkata: Books Way, 2013 (ISBN 978-93-81672-59-4).