The Toronto Zoo has been denied accreditation by the Association of Zoos and Aquariums.
The zoo is still able to operate but has lost the approval of the association, a group of experts in animal management and care.
The group evaluates each zoo on a series of standards, including veterinary care, education programs, safety and governance.
One of its main concerns was the Toronto Zoo's decision to ship three elephants to a sanctuary in the United States.
The zoo will be able to reapply for accreditation next year.
This is the first time it has been denied accreditation in more than three decades.