Emergency crews were called to the scene on Laddie Crescent, in the area of Goreway Drive and Derry Road, around 7:30 a.m.
A paramedics spokesperson said there were 12 people inside the affected residence, seven of whom were transported to hospital.
They were reported to have suffered smoke inhalation and were in non-life-threatening condition.
A spokesperson for Mississauga Fire said a total of six trucks were dispatched to the scene. When crews arrived, smoke was coming out of the garage.
The cause of the blaze is under investigation.
A fire investigator was seen in the home’s burned-out garage Saturday morning.