B Line, B-Line or Line B may refer to the following:

• B (New York City Subway service), a subway route in New York
• 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
• B Line (Los Angeles Metro), a rapid transit line in Los Angeles County, California
• B (Los Angeles Railway), former streetcar service in Los Angeles, US
• RapidRide B Line, a bus route in King County, Washington
• B Line (RTD), a light-rail system in Denver, Colorado
• Butte Regional Transit, a bus system in Butte County, California
• Metro B Line (Minnesota), a planned rapid bus line in Minneapolis-Saint Paul
  • Riverview Corridor, previously known as the B Line

• Line B (Buenos Aires Underground), an underground line in Buenos Aires, Argentina
• B-Line (Hamilton), a proposed light-rail line in Hamilton, Ontario
• Line B (Prague Metro), a subway route in Prague, Czech Republic
• B-Line (Sydney), a bus-rapid-transit system in Sydney, Australia
• B-Line (Vancouver), a bus-rapid-transit system in Vancouver, British Columbia
• Mexico City Metro Line B, a rapid-transit line in Mexico City
• fr:Ligne B du métro de Rennes, a future subway route in Rennes, France

• "B Line" (song), a track on Lamb's album Fear of Fours
• The Eighties Matchbox B-Line Disaster, an English rock band
• Index register, in computing, per outdated British use
• A finding in lung ultrasound

• Bee line (disambiguation)
• B Train (disambiguation)

This disambiguation page lists articles associated with the title B Line.
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