Line 6 may refer to:
Transport Asia China Line 6 (Beijing Subway), a subway line in Beijing Line 6 (Changsha Metro), a metro line in Changsha, Hunan Line 6 (Chengdu Metro), from Pidu District to Tianfu New Area, Chengdu, Sichuan Line 6 (Chongqing Rail Transit), a metro line in Chongqing Line 6 (Fuzhou Metro), from Cangshan District to Changle District, Fuzhou, Fujian Line 6 (Guangzhou Metro), a metro line in Guangzhou, Guangdong Line 6 (Hangzhou Metro), a metro line in Hangzhou, Zhejiang Line 6 (Hefei Metro), a metro line in Hefei, Anhui Line 6 (Jinan Metro), a metro line in Jinan, Shandong Line 6 (Kunming Metro), a metro line in Kunming, Yunnan Line 6 (Nanjing Metro), a future metro line in Nanjing, Jiangsu Line 6 (Ningbo Rail Transit), a metro line in Ningbo, Zhejiang Line 6 (Shanghai Metro), a metro line in Shanghai Line 6 (Shenzhen Metro), a metro line in Shenzhen, Guangdong Line 6 (Suzhou Metro), a metro line in Suzhou, Jiangsu Line 6 (Tianjin Metro), a metro line in Tianjin Line 6 (Wuhan Metro), a metro line in Wuhan, Hubei Line 6 (Xi'an Metro), a metro line in Xi'an, Shaanxi Line 6 (Xuzhou Metro), a metro line in Xuzhou, Jiangsu Line 6 (Xiamen Metro), a metro line in Xiamen and Zhangzhou, Fujian Line 6 (Zhengzhou Metro), a metro line in Zhengzhou, Henan
Other places in Asia Line 6 (Mumbai Metro), also called the Lokhandwala-Jogeshwari-Vikhroli-Kanjurmarg corridor, Mumbai, India Orange Line (Kolkata Metro), India Line 6 (Osaka), an underground rapid transit line in Osaka, Japan Line 6 (Riyadh Metro), Saudi Arabia Seoul Subway Line 6, a line of the Seoul Subway, South Korea Circular line (Taipei metropolitan area), the sixth line to open in the Taipei Metro system, now a line of the New Taipei Metro, Taiwan KLIA Ekspres, called Line 6 at route map Manila Light Rail Transit System Line 6, Metro Manila, Philippines MRT Line 6 (Dhaka Metro), Metro Rail Line 6 in Dhaka, Bangladesh
Europe France Île-de-France tramway Line 6, a rubber-tyred tramway in Île-de-France Paris Metro Line 6, a line of the Paris Metro rapid transit system
Austria U6 (Berlin U-Bahn), a metro line in Berlin U-Bahn U6 (Frankfurt U-Bahn), a metro line in Frankfurt U-Bahn
Spain Barcelona Metro line 6, on the Barcelona–Vallès Line Line 6 (Madrid Metro), one of two circular lines in Madrid
Other places in Europe Line 6 (Moscow Metro), a metro line of the Moscow Metro, Moscow, Russia. Also known as "Kaluzhsko–Rizhskaya line". Line 6 (Saint Petersburg Metro), a metro line of the Saint Petersburg Metro, Moscow, Russia. Also known as "Krasnoselsko–Kalininskaya line". Line 6 (Naples Metro), a light metro line that forms part of the Naples Metro
North America Canada Line 6 (Montreal Metro), a proposed surface-running line of the Montreal Metro Line 6 Finch West, a light rail line in Toronto
Mexico Mexico City Metro Line 6, Mexico Mexico City Metrobús Line 6, a bus rapid transit line in Mexico City Metrorrey Line 6, an upcoming line currently under construction in Monterrey.
United States 6 (New York City Subway service), the 6 Lexington Avenue Local and 6 Pelham Bay Park Express, New York 6 (BMT rapid transit service), the designation for trains that used the BMT Fifth Avenue Line, New York City, New York No. 6 Line (Baltimore streetcar), a bus route operated by the Maryland Transit Administration, Baltimore, Maryland 6 (Los Angeles Railway), former streetcar service
South America Line 6 (São Paulo Metro), a planned extension of the São Paulo Metro, Brazil Santiago Metro Line 6, connecting the communes of Cerrillos and Providencia in Santiago, Chile
Oceania Australia T6 Carlingford Line, Sydney Trains service prior to its closure in 2020 T6 Lidcombe & Bankstown Line, Sydney Trains service, 2024–
Other uses Line 6 (company), a manufacturer of digital modeling guitars, amplifiers and related electronic equipment
See also 6 Train (disambiguation) List of public transport routes numbered 6 List of highways numbered 6