There will be no service on the Yonge-University-Spadina line from St. Clair West to St. George on Saturday and Sunday.
The TTC says shuttle buses will be available.
The line is being shut down for rail installation.
There are also a number of road closure this weekend for a variety of festivals.
The Toronto Triathlon closes the eastbound lanes of the Gardiner Expressway between the Humber and Carlaw Avenue, as well as the northbound lanes of the Don Valley Parkway between the Gardiner and Eglinton Avenue. The closures begin Sunday at 2 a.m. and last until noon.
On Saturday, Bloor St. West is closed between Dufferin St. and Lansdowne Avenue for the Big on Bloor Festival. The street close at at 9 a.m. on Saturday and reopen at 1 a.m. on Sunday.
Thrill of the Grill closes Danforth Avenue is closed from Broadview Avenue to Jackman Avenue on Saturday from 8 a.m. to 5 p.m.
And Youth Day will close Yonge Street from Queen Street to Dundas Street on Sunday from 11 a.m. to 11 p.m.