Greenback may refer to:
In currency:
- Greenback (money), a fiat currency issued during the American Civil War
- United States Note
- Demand Note, issued in 1861–62
- A current (since 1914) United States Federal Reserve Note
- Greenback Party, an American political party that was active between 1874 and 1884 which advocated non-gold-backed government currency, also known as the Greenback Labor Party
- Save the Greenback, organization of U.S. Bureau of Engraving and Printing employees and currency component suppliers opposed to phasing out the paper dollar
Other uses:
- Greenback, Tennessee, United States
- "Greenbacks", a 1955 song by Ray Charles
- Celestion G-12, guitar cabinet loudspeakers
- Greenback cutthroat trout, (Oncorhynchus clarki stomias), the easternmost subspecies of cutthroat trout
- An alternate name for the Bar jack, or Caranx ruber
- A surname