Union is a subway station on Line 1 Yonge–University of the Toronto subway in Toronto, Ontario, Canada. It opened in 1954 as one of twelve original stations on the first phase of the Yonge line, the first rapid transit line in Canada. It was the southern terminus of the line until the opening of the University line in 1963, and is today the inflection point of the U-shaped line. Along with Spadina station and Queens Quay station, it is one of three stations open overnight to support late-night streetcar routes.

Line 1 Yonge–University is a rapid transit line of the Toronto subway. It serves Toronto and the neighbouring city of Vaughan in Ontario, Canada. It is operated by the Toronto Transit Commission, has 38 stations and is 38.4 km (23.9 mi) in length, making it the longest line on the subway system. It opened as the "Yonge subway" in 1954 as Canada's first underground passenger rail line and was extended multiple times between 1963 and 2017. Averaging over 670,000 riders per weekday, Line 1 is the busiest rapid transit line in Canada, and one of the busiest lines in North America.