List of highways numbered 503
The following highways are numbered 503:
Canada
- Alberta Highway 503
- Manitoba Provincial Road 503
- Newfoundland and Labrador Route 503
- Ontario Highway 503
Costa Rica
- National Route 503
India
- National Highway 503
Japan
- Japan National Route 503
United States
- County Road 503
- Maryland Route 503
- County Route 503
- Ohio State Route 503
- Washington State Route 503