Lawyer Bashir Khan says Jamila Bibi was flown out of Toronto on Tuesday afternoon.
He says his client has been barred from re-entering Canada on any visa on the future.
Khan says Bibi fled to Canada in 2007 after being falsely accused of adultery by her husband.
He says traditional Islamic law calls for stoning to death for married people who commit adultery, or she could be a target for honour killing.
Bibi's claim for refugee status was rejected and a last-minute appeal to the Federal Court of Canada this week was rejected.
"The applicant has not presented evidence before this court that could support a finding that she will face risks if she is removed to Pakistan that have not been already assessed on two occasions (by immigration officials)," Justice Marie-Josee Bedard wrote.
"Therefore, and considering that the applicant’s allegation of irreparable harm is based on risks, she has not met her evidentiary burden."
In her letter to the UN, Bibi wrote she has worked hard to establish herself in Saskatoon but her application for a work permit was not processed.
"I know my life would be in danger if I am sent back and I would rather to have peaceful death here than be killed for something that I did not do," she wrote.