Samir Halilovic, Youssef Sakhir and Zakria Habibi knew each other through a local Muslim association in the Eastern Townships.
The three, all in their mid-20s, disappeared around the same time.
Other media have reported that that RCMP and CSIS agents are looking for the men, who may have joined forces with local Islamist fighters in Syria or elsewhere in the Middle East.
RCMP refused to comment on the case to CBC News, other than to confirm they are looking into at least one of the men.
In August, the brother of Habibi posted a missing person alert on an Ismaili Muslim community website.
"My little brother Zakria (known to his friends as “Zack”) has been missing since July 17, 2014. He left for a trip to Turkey on July 13. He contacted us several times during the first couple of days to let us know of his whereabouts. However, since July 17, we have no more news of him," the online posting said.
It said it was unlike Habibi to not be in touch with his family. He was last seen in Konya, Turkey, the missing person alert said. The Facebook page created to try to find Habibi has since been removed from the social networking site.
On Sept. 10, Habibi, who goes by the name Zikria Habibi on Facebook, posted a short message online: "Alhamdulillah im okay." Nothing has been posted — at least not publicly — since then.