Olivia Chow is set to speak to reporters Thursday morning. A news release says she "will start to make her closing case" to voters.
Also Thursday, John Tory picked up an endorsement from Monte Kwinter, the longtime MPP in York Centre.
"I think that John Tory is the right person at the right time," Kwinter said, when publicly endorsing him Thursday morning.
Tory formally entered the mayoral race in February, while Chow threw her hat in the ring in March.
Fellow high-profile candidate Doug Ford joined the race at the very last minute after his brother Mayor Rob Ford withdrew from the race.
Doug Ford is facing calls Thursday to apologize for an alleged derogatory remark he made to a Toronto Star reporter. He denies saying "anything" about the reporter in question.
When the polls open Monday, voters will be able cast their ballot between 10 a.m. and 8 p.m.
More than 161,000 of Toronto's estimated eligible electors voted early during a period of advance voting.