The following is a list and brief history of American football franchises that at one time played in the National Football League (NFL). Note that the list represents NFL franchises that no longer exist, not franchises/teams that relocated. However, during the 1920s it is hard to tell if some teams changed nicknames from year to year or if each nickname represented a new franchise. It was also not uncommon for two or more teams to have the same nickname during the same season. No NFL franchise has folded since 1952. The Buccaneers, Colts, Cowboys, Giants, Lions, Panthers, and Texans franchises listed on this page are not the current franchises of those names.
A defunct team, in this case, refers to a team which has had the rights to have a team returned to the NFL (or league collective at the time).
- Teams that won an NFL championship are marked with an asterisk (*).
- Akron Pros / Indians* (1920-26)
- Brooklyn Lions (1926)
- Buffalo All Americans / Bisons / Rangers (1920-29)
- Canton Bulldogs* (1920-26)
- Chicago Tigers (1920)
- Cincinnati Celts (1921)
- Cleveland Bulldogs* (1923-27)
- Cleveland Tigers (1920-21)
- Columbus Panhandles/Tigers (1920-26)
- Dayton Triangles (1920-29)
- Detroit Heralds (1920)
- Detroit Tigers (1921)
- Detroit Panthers (1925-26)
- Detroit Wolverines (1928)
- Duluth Kelleys/Eskimos (1923-27)
- Evansville Crimson Giants (1921-22)
- Frankford Yellow Jackets* (1924-31)
- Hammond Pros (1920-26)
- Hartford Blues (1926)
- Kansas City Blues/Cowboys (1924-26)
- Kenosha Maroons (1924)
- Los Angeles Buccaneers (1926)
- Louisville Breckenridges (a.k.a. "Brecks") (1921-23)
- Louisville Colonels (1926)
- Massillon Tigers (Attended the August 1920 meeting, but never fielded a team in the APFA/NFL)
- Milwaukee Badgers (1922-26)
- Minneapolis Marines (1921-24)
- Minneapolis Red Jackets (1929-31)
- Muncie Flyers (1920-21)
- New York Brickley Giants (1921)
- New York Yankees (1926-28)
- Newark Tornadoes (1930)
- Oorang Indians (1922-23)
- Orange Tornadoes (1929)
- Pottsville Maroons/Boston Bulldogs (1925-29)
- Providence Steam Roller* (1925-31)
- Racine Legion (1922-24)
- Racine Tornadoes (1926)
- Rochester Jeffersons (1920-25)
- Rock Island Independents (1920-25)
- Staten Island Stapletons (1929-32)
- St. Louis All Stars (1923)
- Syracuse Pros (1921, it is disputed whether or not this team actually joined the league)
- Toledo Maroons (1922-23)
- Tonawanda Kardex (1921)
- Washington Senators (1921)
- Youngstown Patricians (1922, joined league and had schedule planned, but never played)
- Brooklyn Dodgers/Tigers (1930-44)
- Cincinnati Reds (1933-34)
- Cleveland Indians (1931)
- St. Louis Gunners (1934)
- Baltimore Colts (1950)
- Boston Yanks (1944-48) / New York Bulldogs (1949) / New York Yanks (1950-51)
- Dallas Texans (1952)
These are all teams that applied to join the NFL but were refused entry. Some existed only as proposals, but others had full organizations. Unless otherwise noted, each team folded after their unsuccessful bid to join the NFL.
- Los Angeles Bulldogs (1936) Approved as a probational franchise with the intention of becoming a full-fledged member in 1937. However, the Cleveland Rams were admitted in their place, due to travel cost concerns. The Bulldogs would go on to play in other leagues until 1948, while the Rams, coincidentally, would move to Los Angeles themselves in 1946.
- Pennsylvania Keystoners (1940) Proposed merger of the Philadelphia Eagles and Pittsburgh Pirates that was rejected by league ownership.
- Buffalo Bills (AAFC) (1950) Members of the All-America Football Conference. Four NFL owners blocked Buffalo's entry into the NFL. Current Bills franchise is unrelated other than in name.
- Memphis Grizzlies (1975) Members of the World Football League. Unsuccessfully sued NFL to attempt to force admission (see: Mid-South Grizzlies v. NFL). Team later remanifested as the Tampa Bay Bandits.
- New Jersey Generals (1986). Members of the United States Football League. Owner Donald Trump was among those seeking to force a merger of the USFL and the NFL, but were unable to do so.
- Memphis Hound Dogs (1993). Proposed expansion team. Later played as Memphis Mad Dogs in CFL USA in 1995.
- Baltimore Bombers (1993). Proposed expansion team.
- St. Louis Stallions (1993). Proposed expansion team.