QuickLink 40 is a limited stop bus route operated by the Maryland Transit Administration in Baltimore and its suburbs. Formerly the Quickbus 40, the line was discontinued in June 2017 as part of the BaltimoreLink system rebranding along with the other "Quickbus" limited-stop routes. On August 27, 2023, QuickBus 40, was re-launched after it was discontinued in 2017.

The Maryland Transit Administration (MTA) is a state-operated mass transit administration in Maryland, and is part of the Maryland Department of Transportation. The MTA operates a comprehensive transit system throughout the Washington-Baltimore metropolitan area. There are 80 bus lines serving the Baltimore Metropolitan Area, along with rail services that include the Light Rail, Metro Subway, and MARC Train. In 2023, the system had a ridership of 52,922,000, or about per weekday as of the fourth quarter of 2023.