List of highways 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 (India)

Japan

• Japan National Route 503

United States

• County Road 503 (Brevard County, Florida)
• Maryland Route 503
• County Route 503 (New Jersey)
• Ohio State Route 503
• Washington State Route 503

• Puerto Rico Highway 503