The following highways are numbered 320:
Canada
United States
- U.S. Route 320 (former)
- Connecticut Route 320
- Georgia State Route 320
- Florida State Road 320
- Hawaii Route 320
- Kentucky Route 320
- Louisiana Highway 320
- Maryland Route 320
- Montana Secondary Highway 320
- Nevada State Route 320
- New Mexico State Road 320
- New York State Route 320
- Ohio State Route 320
- Pennsylvania Route 320
- Tennessee State Route 320
- Texas State Highway 320
- Utah State Route 320
- Virginia State Route 320
- Wyoming Highway 320