The suspect, who was not immediately identified, will be appearing in court (at 2201 Finch Avenue West) at 10 a.m. today.
Police say emergency officials responded to a call Monday night at a townhouse complex (in the Burnhamthorpe Road and Dundas Street area) and found three bodies.
Const. Victor Kwong says the suspect is related to the victims, and that when police arrived at the scene, the bodies of two women and one man aged between 49 and 76 were found with obvious signs of injury.
The suspect was found a short distance from the scene and taken into custody.
Police say they are not actively canvassing witnesses but anyone with information relevant to the case should come forward.
"All these people are related and for that reason at this point we are not giving out any identification about the suspect or the victims, as all the remaining next of kin have not been notified," said Kwong.