Imam Syed Soharwardy and 37 other Muslim leaders from across the country have issued a fatwa against the group currently trying to attract supporters to its war in Syria and Iraq.
Soharwardy, the founder of the Islamic Supreme Council of Canada, says the Islamic State is violating Muslim law.
He says as a result the group and anyone supporting them will no longer be considered to be Muslim.
Soharwardy also has harsh words for Prime Minister Stephen Harper and the federal government for equating ISIL followers with jihadists.
He says to Muslims that word simply means to struggle and using it might be leading to more sympathy for the terrorist group.