Peel Region police say they were called to a home Tuesday afternoon on Colonial Drive in the city west of Toronto for a report of a disturbance.
When they arrived they say they found a woman behaving "strangely."
Two-year-old Evadne Williams-Scott was found with no vital signs and "obvious signs of trauma."
Her mother, Teresa Williams, is set to appear in court in Brampton, Ont., today and police say she will face a charge of second-degree murder.
It's the city's first homicide of the year.