That will make Canada the second NATO member nation after the United States to attack Islamic State positions in Syria, which have also been hit by jets from Jordan and the United Arab Emirates.
Harper also said Canada plans to extend its six-month mission against Islamic State by a year, to the end of March 2016. Canada has around 70 special forces troops in northern Iraq and six Canadian jets are taking part in U.S.-led bombing missions against Islamic State in Iraq.
Harper, facing a tough challenge to retain power in October's general election, portrays rival political parties as weak on terror and says only his Conservatives properly understand the threat Islamic State poses to Canada.
Both main opposition parties said expanding the mission would drag Canada deeper into a war it should have no part in.
Harper told legislators that Canada must strike at the Syrian power base of the Islamic State, formally known as the Islamic State of Iraq and the Levant (ISIL).