The following highways are numbered 403:
Canada Manitoba Provincial Road 403 Newfoundland and Labrador Route 403 Highway 403 (Ontario)
Costa Rica National Route 403
Croatia D403 road
Hungary Main road 403 (Hungary)
Japan Japan National Route 403
Thailand Thailand Route 403
United States Georgia State Route 403 (unsigned designation for Interstate 85) Indiana State Road 403 (former) New York: New York State Route 403 County Route 403 (Albany County, New York) County Route 403 (Erie County, New York) North Carolina Highway 403 Pennsylvania Route 403 Puerto Rico Highway 403 Rhode Island Route 403 South Carolina Highway 403 Virginia State Route 403 Washington State Route 403