D Line may refer to:
Transportation
edit- Line D (Buenos Aires Underground), an underground line in Buenos Aires, Argentina
- D Line (Los Angeles Metro), a rapid transit line in Los Angeles County, California
- Line D (Prague Metro), a subway route under construction in Prague, the Czech Republic
- Line D (Rome Metro), potential line of the Rome Metro system
- D Line (RTD), a light rail line in Denver
- Green Line D branch, a light rail line in Boston
- D (New York City Subway service), a subway route in New York
- RapidRide D Line, a bus route in Seattle, Washington, United States
- Metro D Line (Minnesota), a bus rapid transit line in Minneapolis, Minnesota, United States
- D (Los Angeles Railway), a former streetcar line in Los Angeles, California
Other uses
edit- D-line, Port Harcourt, a neighborhood in Port Harcourt, Nigeria
- D-line (IRC), a command in IRCd
- D-line, a spectral line of the Fraunhofer lines