Donut Day is an annual event that was started and continues to be put on by the Salvation Army, a national charitable organization. The Salvation Army started the Donut Day effort in 1938 as a means of providing comfort and relief for cold, hungry American soldiers in French trenches during World War I; Salvation Army workers would pass out donuts and coffee in order to relieve the discomfort caused by inadequate or unappealing food rations for soldiers and other servicemen. The donut became such an iconic symbol of the United States' war effort that, according to the Salvation Army, this event is the origin of the "doughboy" nickname that was applied to American servicemen during World War I.
The first Donut Day was held in order to raise funds to allow this donuts and coffee support program to continue. Male and female Salvation Army workers were present on battlefields in order to perform Christian missionary services during wartime, but the individuals who passed out donuts tended to be women, who were referred to as donut lassies. These women would provide other comforting items to soldiers, including stamps, writing materials and hot meals. Donut lassies often had to be inventive because battlefield supplies were so scarce; some even took to frying donuts in soldiers' helmets.