Details of the proposed deal covering more than 2,600 flight attendants were not immediately available.
The airline said the proposed five-year deal with WestJet's Flight Attendant Association Board replaces an earlier memorandum of agreement.
WestJet and the association board have committed to honour the tentative agreement, which includes a dispute resolution process, the airline said.
Flight attendants will have a chance to review the proposed agreement starting Friday and be able to vote on it during a two-week period starting Nov. 10.
The Flight Attendant Association board is part of the ProActive Communication Team, WestJet's employee association that represents non-management employees.