A third person has died after Monday's bus crash on the 401, according Ontario Provincial Police (OPP).
Police say a 60-year-old Weiping Lu, a tourist from China, died in hospital Thursday.
Xueying Ye, 57, and Changlin Xu, 54, also of China, had been pronounced dead earlier this week.
The bus, carrying Chinese tourists, veered off the highway and hit a rock cut, sending two dozen people to hospital. The driver has suggested the steering wheel locked up, causing him to lose control. OPP say their investigation into the crash is ongoing.
U.S.-based Union Tour Express, which operates the bus, maintains the bus was safe. The company has has no prior serious crashes according to U.S. regulators.
Chinese officials have called on the travel agency to cover medical costs for the victims and their families.