Doughboy was an informal term for a member of the United States Army or Marine Corps, especially used to refer to members of the American Expeditionary Forces in World War I, but initially used in the Mexican-American War of 1846-48. A popular mass-produced sculpture of the 1920s, the Spirit of the American Doughboy, shows a U.S. soldier in World War I uniform.
The term was still in use as of the early 1940s – for instance in the 1942 song "Johnny Doughboy Found a Rose in Ireland," recorded by Dennis Day, Kenny Baker and Kay Kyser, among others; as well as the 1942 musical film Johnny Doughboy – but was gradually replaced during World War II by "G.I.". 
Although best known from its usage for American troops in the First World War, the origins of the term are unclear. The word was in wide circulation a century earlier in both Britain and America, albeit with different meanings. Horatio Nelson's sailors and the Duke of Wellington's soldiers in Spain, for instance, were both familiar with fried flour dumplings called "doughboys", the precursor of the modern doughnut.
Independently, in the former colonies, the term had come to be applied to baker's young apprentices, i.e. "dough-boys". The New World version of doughboy was a linguistic cousin to "dough-head", a colloquialism for stupidity in 19th Century America. In Moby-Dick, Herman Melville nicknamed the timorous cabin steward "Doughboy." 
Doughboy as applied to the infantry of the U.S. Army first appears in accounts of the Mexican-American War of 1846-48, without any precedent that can be documented. A number of theories have been put forward to explain this usage:
- Cavalrymen used the term to deride foot soldiers, because the brass buttons on their uniforms looked like the flour dumplings or dough cakes called "doughboys", or because of the flour or pipe clay which the soldiers used to polish their white belts.
- Observers noticed U.S. infantry forces were constantly covered with chalky dust from marching through the dry terrain of northern Mexico, giving the men the appearance of unbaked dough or the mud bricks of the area known as adobe, with "adobe" transformed into "doughboy".
- The soldiers' method of cooking field rations of the 1840s and 1850s into doughy flour-and-rice concoctions baked in the ashes of a camp fire. This does not explain why only infantryman received the appellation.
The American usage was adopted in the UK by c.1917.
One explanation offered for the usage of the term in World War I is that female Salvation Army volunteers went to France to cook millions of doughnuts and bring them to the troops on the front line, although this explanation ignores the usage of the term in the earlier war.
- Frank Buckles - longest-living doughboy
- Digger - equivalent for Australian soldiers, originated in World War I
- Dogface (military)
- Poilu - equivalent term for French soldiers of World War I
- Tommy Atkins - equivalent term for British soldiers of World War I
- Evans, Ivor H. (ed.) (1981) Brewer's Dictionary of Phrase and Fable New York: Harper & Row, p.353 ISBN 0-06-014903-5
- George, John B. (1948) Shots Fired In Anger, Samworth Press. pp.xi,xii,21. Lt. John George, an Army officer writing a World War II autobiographical postwar combat memoir in May 1947, freely used the term to describe himself and his fellow U.S. Army infantrymen.
- Chapter 34ff
- Beale, Paul (ed.) (1989) A Concise History of Slang and Unconventional English: From "A Dictionary of Slang and Unconventional English" by Eric Partridge New York: Macmillan. p.134. ISBN 9780026053501
- Dana, Napoleon Jackson Tecumseh (1990). Monterrey Is Ours! The Mexican War Letters of Lieutenant N.J.T. Dana, 1845-1847, Lexington Kentucky: University of Kentucky Press. ISBN 0-8131-1703-8. Lt. Dana, an infantryman in the Mexican-American War, wrote in a letter posted during the campaign, "We 'doughboys' had to wait for the artillery to get their carriages over."
- Chamberlain, Samuel (1965). My Confessions: Recollections of a Rogue, Austin: Texas State Historical Association. Chamberlain, a horse-mounted Dragoon in the Mexican-American War, wrote in his memoirs years later, "No man of any spirit and ambition would join the 'Doughboys' and go afoot."
- Taylor, David A. (March 1998) "The History of the Doughnut" Smithsonian Magazine
- Hanlon, Michael E. "Origins of 'Doughboy'" Doughboy Center: Stories of the American Expeditionary Force
- Gaimo, Cara (September 18, 2015) "The Sweet, Love Affair Between Cops and Doughnuts" Atlas Obscura
- Staff (February 28, 2011) "Last 'Doughboy' dies at 110" KNOX News
- Faulstich, Edith. M. "The Siberian Sojourn" Yonkers, N.Y. (1972–1977)
- Gawne, Jonathan. Over There!: The American Soldier in World War I (1999)- 83 pages, heavily illustrated
- Grotelueschen, Mark Ethan. The AEF Way of War: The American Army and Combat in World War I (2006) excerpt and text search
- Gutièrrez, Edward A. Doughboys on the Great War: How American Soldiers Viewed Their Military Experience (2014)
- Hallas, James H. Doughboy War: The American Expeditionary Force in World War I (2nd ed. 2009) online edition; includes many primary sources from soldiers
- Hoff, Thomas. US Doughboy 1916-19 (2005)
- Kennedy, David M. Over Here: The First World War and American Society (1980) excerpt and text search
- Nelson, James Carl. The Remains of Company D:A Story of the Great War (2009)
- Rubin, Richard The Last of the Doughboys: the forgotten generation and their forgotten world war ISBN 9780547554433 plus online webcast presentation of book
- Schafer, Ronald. America in the Great War (1991)
- Skilman, Willis Rowland. The A.E.F.: Who They Were, what They Did, how They Did it (1920) 231 pp; full text online
- Smith, Gene. Until the Last Trumpet Sounds: The Life of General of the Armies John J. Pershing (1999), popular biography.
- Snell, Mark A. Unknown Soldiers: The American Expeditionary Forces in Memory and Remembrance (2008)
- Thomas, Shipley. The History of the A. E. F. (1920), 540pp; full text online
- Votow, John. The American Expeditionary Forces in World War I (2005) - 96 pp; excerpt and text search
- Werner, Bret. Uniforms, Equipment And Weapons of the American Expeditionary Forces in World War I (2006)
|Wikimedia Commons has media related to Doughboys.|
- Doughboy Center stories from the AEF