List of highways numbered 121
Route 121 or Highway 121 can refer to multiple roads:
Argentina
Canada
Costa Rica
Japan
Nigeria
United Kingdom
 A121 road . A121 road .
- B121 road.
United States
 U.S. Route 121 (proposed) U.S. Route 121 (proposed).svg.png) U.S. Route 121 (former) U.S. Route 121 (former)
 
 Alabama State Route 121 (former) Alabama State Route 121 (former)
 Arkansas Highway 121 Arkansas Highway 121
 California State Route 121 California State Route 121
 Colorado State Highway 121 Colorado State Highway 121
 Connecticut Route 121 Connecticut Route 121
 Florida State Road 121 Florida State Road 121
 Georgia State Route 121 Georgia State Route 121
 Hawaii Route 121 Hawaii Route 121
 Illinois Route 121 Illinois Route 121
 Indiana State Road 121 Indiana State Road 121
 K-121 (Kansas highway) (former) K-121 (Kansas highway) (former)
 Kentucky Route 121 Kentucky Route 121
 Louisiana Highway 121 Louisiana Highway 121
 Maine State Route 121 Maine State Route 121
 Maryland Route 121 Maryland Route 121
 Massachusetts Route 121 Massachusetts Route 121
 M-121 (Michigan highway) M-121 (Michigan highway)
 Minnesota State Highway 121 Minnesota State Highway 121
 Missouri Route 121 Missouri Route 121
 Nebraska Highway 121 Nebraska Highway 121
 Nevada State Route 121 Nevada State Route 121
 New Hampshire Route 121 New Hampshire Route 121
 New Mexico State Road 121 New Mexico State Road 121
 New York State Route 121 New York State Route 121 County Route 121 (Herkimer County, New York) County Route 121 (Herkimer County, New York)
 County Route 121 (Jefferson County, New York) County Route 121 (Jefferson County, New York)
 County Route 121 (Montgomery County, New York) County Route 121 (Montgomery County, New York)
 County Route 121 (Niagara County, New York) County Route 121 (Niagara County, New York)
 County Route 121 (Seneca County, New York) County Route 121 (Seneca County, New York)
 County Route 121 (Steuben County, New York) County Route 121 (Steuben County, New York)
 County Route 121 (Sullivan County, New York) County Route 121 (Sullivan County, New York)
 
 North Carolina Highway 121 North Carolina Highway 121
 Ohio State Route 121 Ohio State Route 121
 Pennsylvania Route 121 Pennsylvania Route 121
 Rhode Island Route 121 Rhode Island Route 121
 South Carolina Highway 121 South Carolina Highway 121
 Texas State Highway 121 Texas State Highway 121 former 121 Tollway (now Sam Rayburn Tollway) former 121 Tollway (now Sam Rayburn Tollway)
 Texas State Highway Loop 121 Texas State Highway Loop 121
 Texas State Highway Spur 121 (former) Texas State Highway Spur 121 (former)
 Farm to Market Road 121 Farm to Market Road 121
 
 Utah State Route 121 Utah State Route 121
 Vermont Route 121 Vermont Route 121
 Virginia State Route 121 Virginia State Route 121 Virginia State Route 121 (1923-1926) (former) Virginia State Route 121 (1923-1926) (former)
 Virginia State Route 121 (1927-1928) (former) Virginia State Route 121 (1927-1928) (former)
 Virginia State Route 121 (1928-1933) (former) Virginia State Route 121 (1928-1933) (former)
 
 Washington State Route 121 Washington State Route 121
 Wisconsin Highway 121 Wisconsin Highway 121
- Territories
| Preceded by 120 | Lists of highways 121 | Succeeded by 122 | 
  











