List of public transport routes numbered 4

In public transport, Route 4 may refer to:


 * Route 4 (MTA Maryland), a bus route in the suburbs of Baltimore, United States
 * Barcelona Metro line 4 in Barcelona, Spain
 * NWFB Route 4, a bus route in Hong Kong
 * London Buses route 4 in London, United Kingdom
 * Line 4 (Madrid Metro) in Madrid, Spain
 * Line 4 Yellow (Montreal Metro) in Montreal, Canada
 * 4 (New York City Subway service), a subway line in New York City, United States
 * Shanghai Metro Line 4 in Shanghai, China