Greenback(s) may refer to:
Currency Greenback (1860s money), a fiat currency issued during the American Civil War United States Note, paper money issued from 1862 to 1971 Greenback, a nickname used for the United States dollar in the financial press in other countries
Fish Greenback cutthroat trout (Oncorhynchus clarki stomias), the easternmost subspecies of cutthroat trout in the US Greenback flounder (Rhombosolea tapirina), a species of flounder found in Australasian waters Greenback horse mackerel (Trachurus declivis), a species of jack found in Australasian waters Greenback stingaree (Urolophus viridis), a stingray found in SE Australian waters
Music "Greenbacks", a 1955 song by Ray Charles "Greenbacks" (Once Upon a Time), an episode of the seventh season of Once Upon a Time
Other uses Baron Silas Greenback, a fictional villainous toad in Danger Mouse (TV series) Greenback, Tennessee, a city in the United States Greenback Party, an American political party active between 1874 and 1884 which advocated non-gold-backed government currency