Fire Chief Jim Sales confirmed the suspension of the firefighters at a news conference on Thursday but refused to offer up any specifics of the case.
First published in the National Post on Aug. 10, one tweet reads "reject a woman and she will never let it go. One of the many defects of their kind. Also weak arms."
Another reads "would swat her in the back of the head been considered abuse or a way to reset the brain?"
The suspended firefighters have been identified as Matt Bowman and Lawaun Edwards, and the remarks by both have since been deleted.
Sales told reporters that Toronto fire had launched an investigation into the incident that he called "a personnel matter" and an "isolated incident that we'll deal with."
He said he was first informed about the tweets after media reports surfaced.
"If we have a problem we need to do more," Sales said, adding that his staff would be reviewing the "education and enforcement" of the city's social media policy.
"We don't condone negativity brought to the fire service by individual members or other members," he said.
South Park quotes
The firefighters union said the tweets were quoting characters on TV shows, including one from the popular cartoon South Park.
"I don't know who the tweets were meant for but it's possible they were taken out of that context," said Frank Ramagnano with the Toronto Professional Fire Fighters' Association.
The CBC's Steven D'Souza said women currently make up 5.2 per cent of the service, and visible minorities just 4.2 per cent.
The fire chief said social media is in the public realm and when Toronto fire staff use it, they should reflect a "positive" image.
"In the public domain it's important for all of us to demonstrate a positive image of the Toronto Fire Service," he said.