| State: | NM |
| Type: | SR |
| Route: | 321 |
| Map Custom: | yes |
| Length Mi: | 4.606 |
| Length Ref: | [1] |
| Direction A: | West |
| Terminus A: | in Causey |
| Direction B: | East |
| Terminus B: | at the Texas–New Mexico state line |
| Counties: | Roosevelt |
| Previous Type: | NM |
| Previous Route: | 320 |
| Next Type: | NM |
| Next Route: | 322 |
State Road 321 (NM 321) is a 4.6adj=midNaNadj=mid state highway in the US state of New Mexico. NM 321's western terminus is at NM 114 in Causey, and the eastern terminus is at Farm to Market Road 54 (FM 54) at the Texas–New Mexico state line.