The Queen Street subway line was a proposed subway line for the city of Toronto, Ontario, Canada. It was one of many subway lines planned for, but has yet to be built by the Toronto Transit Commission.

The idea for a Queen subway line began with streetcar subway line proposals for both Queen Street and Bloor Street by the Department of Roads and Bridges of the City of Toronto Engineers in 1911. It was not until the 1940s that the Queen Street line re-emerged as a potential project.

The 1944 TTC Rapid Transit Proposals for a Queen Street route and a referendum on January 1, 1946, brought the Queen subway line back to life. The line called for an open-cut with right of way and built to the north of the existing Queen streetcar line.

The Yonge line was built first and subsequently, it was decided to build an east–west subway line along Bloor Street and Danforth Avenue instead of Queen due to changes in traffic and population patterns.

The existing Queen Street streetcar line is the longest and most heavily used. However, the volume of riders did not justify a subway line in the 1960s.

A rough platform, partial station is all that remains of a station and the proposed Queen subway line with access from a door from the existing Queen station.

Stations on the proposed Queen line:

Later changes to the line would have extended the subway to the Humber Loop in the west and Eglinton – Don Mills to the northeast end: