Gray Line or Grey Line may refer to:
Transportation Gray Line Worldwide, an international sightseeing bus operator Grey Line (Bangkok), a planned monorail line in Bangkok, Thailand Grey Line (Delhi Metro), Delhi, India Gray Coach, a former Canadian inter-city bus line based in Toronto E Embarcadero, San Francisco, California Jubilee line, London, England Line 6 Finch West, Toronto, Canada Line 9 (Shenzhen Metro), Shenzhen, China Metro (Minnesota), lettered lines are color-coded "METRO Gray", Minneapolis—Saint Paul, Minnesota Olympic Park railway line, Sydney, Australia Pujiang line, Shanghai, China Serpukhovsko-Timiryazevskaya line, known as the Grey Line, Moscow, Russia
New York City Subway BMT Canarsie Line L (New York City Subway service) S (New York City Subway service), three separate rapid transit subway shuttles
Other uses Grayline lascar Terminator (solar) or grey line, delimiting the illuminated and dark sides of a planetary body The Long Gray Line