A tenancy does not end when a fixed term lease expires, unless:

• The landlord or the tenant gives proper notice to end the tenancy for a reason permitted in the RTA.
• The landlord and tenant both agree that the tenancy will end.
• The LTB or the court has issued an order ending the tenancy.

Otherwise the tenancy will renew automatically with the same terms and conditions. However the tenancy will become a month-to-month agreement instead of a yearly one, or a week-to-week agreement if the tenant pays rent weekly. Once the tenancy becomes a month-to-month agreement or a week-to-week agreement, the usual rules about rent increases apply.

Source: www.sjto.gov.on.ca