The following highways are numbered 303:
Canada New Brunswick Route 303 Nova Scotia Route 303 Prince Edward Island Route 303 Quebec Route 303 Saskatchewan Highway 303
China China National Highway 303
Costa Rica National Route 303
India National Highway 303 (India)
Japan Japan National Route 303
Philippines N303 highway (Philippines)
United Kingdom A303 road (Basingstoke-Honiton)
United States Arizona State Route 303 Arkansas Highway 303 Alabama Highway 303 Georgia State Route 303 Indiana State Road 303 Kentucky Route 303 Louisiana Highway 303 Maryland Route 303 Minnesota State Highway 303 (former) New Jersey Route 303 (never built) New York: New York State Route 303 County Route 303 (Albany County, New York) County Route 303 (Erie County, New York) County Route 303 (Westchester County, New York) North Carolina Highway 303 (former) Ohio State Route 303 Pennsylvania Route 303 (former) South Carolina Highway 303 Tennessee State Route 303 Texas: Texas State Highway 303 (former) Texas State Highway Spur 303 Farm to Market Road 303 Urban Road 303 (signed as Farm to Market Road 303) Utah State Route 303 Virginia State Route 303 Washington State Route 303
Other areas: Puerto Rico Highway 303 U.S. Virgin Islands Highway 303