Blue Line or Blueline may refer to:

Transportation

Africa

• Blue Line (Lagos Transit), Lagos, Nigeria

• Blue Line, part of the Abuja Light Rail Network in Abuja, Nigeria

Asia

China

• Line 2 (Beijing Subway), Beijing

• East Rail line, Hong Kong

• Island line (MTR), Hong Kong

India

• Blue Line (Namma Metro), Bengaluru

• Blue Line (Chennai Metro), Chennai

• Blue Line (Delhi Metro), Delhi

• Blue Line (Hyderabad Metro), Hyderabad

• Blue Line (Kolkata Metro), Kolkata

• Blue Line (Lucknow Metro), Lucknow

• Blue Line (Mumbai Metro), Mumbai

South Korea

• Busan Metro Line 4, Busan

• Seoul Subway Line 1, Dark Blue Line, Seoul

• Seoul Subway Line 4, Light Blue Line, Seoul

Taiwan

• Blue line (Taichung MRT), Taichung

• Bannan line, Taipei

Others

• Blue Line (Bangkok), Bangkok, Thailand

• Blue Line (Dubai Metro), Dubai

• Cibubur Line of Jabodebek LRT, Jakarta, Indonesia

• MRT Line 3 (Metro Manila), known as Blue Line before 2012, Manila, Philippines

• Line 1 (Riyadh Metro), Blue Line, Riyadh, Saudi Arabia

• Downtown Line, Singapore

• Blue Line (Yokohama), also called Lines 1 & 3, Yokohama, Japan

• Blue Line (Jerusalem Light Rail)

Europe

• Blue Line (airline), based in France

• Blue Line (Lisbon Metro), Portugal

• Blue line (Stockholm Metro), Sweden

• Blue Line International, a former ferry service in the Adriatic Sea

• Barcelona Metro line 5, often called "Línia Blava" (Blue Line), Barcelona, Spain

• Barcelona Metro line 6, Barcelona, Spain

• Paris Metro Line 2, Paris, France

• Piccadilly line, London, England

• Sheffield Supertram Blue Line, United Kingdom

• Tyne and Wear Metro of Newcastle upon Tyne, UK (Former line)

• Victoria line, London, England

North America

Canada

• Blue Line (Calgary), Calgary, Alberta

• Blue Line (Montreal Metro), Montreal, Quebec

• Line 4 (O-Train), the Airport Link of Ottawa's O-Train (Line 4)

• Line 3 Scarborough, Toronto, Ontario

• Viva Blue, York Region, Ontario

Mexico

• Blue Line (Mexico City Metro)

• Blue Line (Mexico City Metrobús)

United States

California

• A Line (Los Angeles Metro), Los Angeles County

• Blue Line (SacRT), Sacramento

• Blue Line (San Diego Trolley), San Diego

• Blue Line (BART), San Francisco Bay Area

• N Judah, a Muni Metro light rail line in San Francisco

New York City

• The Harlem Line of the Metro-North Railroad

• The Hoboken–33rd Street route of the PATH Train

Any of the New York City Subway services that use the IND Eighth Avenue Line and its branches:

• A Eighth Avenue Express

• C Eighth Avenue Local

• E Eighth Avenue Local

• The former K Eighth Avenue Local

• The Rockaway Park Shuttle, which formerly contained a blue route bullet

• The Port Jefferson Branch of the Long Island Rail Road

• The former JFK Express of the New York City Subway

• The future T Second Avenue Local of the New York City Subway

• The West Hempstead Branch of the Long Island Rail Road

• The Staten Island Railway

Other

• ARTx Blue Line, formerly Rapid Ride, Albuquerque, New Mexico

• Blue Line (MARTA), Atlanta, Georgia

• Blue Line (CapMetro), Austin, Texas

• Blue Line (MBTA), Boston, Massachusetts

• Lynx Blue Line, Charlotte, North Carolina

• Blue Line (CTA), Chicago, Illinois

• Blue Line (RTA Rapid Transit) (light rail), Cleveland, Ohio

• Blue Line (DART), Dallas, Texas

• Trinity Railway Express, Dallas, Texas

• H Line (RTD), Denver, Colorado

• Metro Blue Line (Minnesota), Minneapolis, Minnesota

• Atlantic City Line, a commuter rail line New Jersey

• Grove Street – Newark Penn, a light rail line in Newark, New Jersey

• North Jersey Coast Line, a commuter rail line New Jersey

• Blue Line (Pittsburgh), Pittsburgh, Pennsylvania

• Market–Frankford Line, Philadelphia, Pennsylvania

• MAX Blue Line, Portland, Oregon

• Blue Line (St. Louis MetroLink), St. Louis, Missouri

• Blue Line (Sound Transit), a proposed extension in Seattle, Washington

• Swift Blue Line, Snohomish County, Washington

• Blue Line (TRAX), a light rail line in the Salt Lake City, Utah area

• Blue Line (Washington Metro), Washington, DC

• Tomorrowland Transit Authority PeopleMover, Walt Disney World, Florida

Oceania

• Eastern Suburbs & Illawarra Line, Sydney, Australia

• Leppington & Inner West Line, Sydney, Australia

• South Coast Line, New South Wales, Australia

South America

• Line 1 (São Paulo Metro), São Paulo, Brazil

Other

• Blue Line (album), by Yae

• Blue line (ice hockey), the line between center ice and each team's zone

• Blue Line (withdrawal line), the UN drawn demarcation line dividing Lebanon from Israel and the Golan Heights

• Blue Line (New York State), delineates the Adirondack and Catskill parks of New York's Forest Preserve

• BlueLine Grid, a mobile communications platform that connects civil service employees

• Blueline, a 2019 EP by twlv

• The "blue line", mark on an airspeed indicator for a multi-engine aircraft

• The blue-line printing process for copying using the diazo chemical process, also known as whiteprint

• The Blueline Blaster, nickname of Hy Buller (1926–1968), All Star NHL ice hockey player

• Blue line, a diagram in method ringing which shows the structure of a method

• Blue-line stream, year-round streams that are typically denoted on maps with solid blue lines

• "Blue Lines", a song by the American band Bright from the album Full Negative (or) Breaks