B Line, B-Line or Line B may refer to the following:
Transportation
- B (New York City Subway service), a subway route in New York
- B-Line (Sydney), a bus-rapid-transit system in Sydney, Australia
- B-Line (Vancouver), a bus-rapid-transit system in Vancouver, British Columbia
- B-Line (Norfolk Southern), a freight-rail line in Virginia
- Green Line B branch, a light-rail line in Boston, Massachusetts
- B-Line Rivalry, a sports rivalry between Boston College and Boston University
- Line B (Buenos Aires Underground), an underground line in Buenos Aires, Argentina
- B Line (Los Angeles Metro), a subway line in Los Angeles, US
- B (Los Angeles Railway), former streetcar service in Los Angeles, US
- Line B (Prague Metro), a subway route in Prague, Czech Republic
- Mexico City Metro Line B, a rapid-transit line in Mexico City
- RapidRide B Line, a bus route in King County, Washington
- B-Line (Hamilton), a proposed light-rail line in Hamilton, Ontario
- B Line (RTD), a light-rail system in Denver, Colorado
- Butte Regional Transit, a bus system in Butte County, California
- B Line (Minnesota), a planned rapid bus line in Minneapolis-Saint Paul
- Riverview Corridor, previously known as the B Line
Music
- "B Line" (song), a track on Lamb's album Fear of Fours
- The Eighties Matchbox B-Line Disaster, an English rock band
Computers
- An old British term for Index register
See also
- Bee line (disambiguation)
- B Train (disambiguation)