Joy Smith says the film, based on the 2011 novel about a dominant-submissive sexual relationship, glamorizes violence against women.
"This movie tries to make this kind of thing normal," Smith said.
"And perpetrators try to make this kind of thing normal behaviour. It's not normal behaviour. Women don't have to hurt. Women should be treated with dignity."
Smith is calling on Canadians to boycott the movie and donate the money they would have spent on a ticket to a women's shelter.
The behaviour in the movie reflects techniques used by traffickers on victims, she said.
"I find it disturbing that this is being advertised as a date night movie, a love movie. It's not love at all. It's violence against women. And you know we are trying in this country to stop violence against women," she said.
Overall, Smith says the message the movie sends is one of unhealthy sexual relationships.