When a tenant decides to move, they must provide a written notice to the landlord. In most cases, the notice provided to the landlord must be at least 60 days before the last day of the rental period, or their lease. For example, if it is a monthly tenancy that begins on the first day of each month and the tenant gives the landlord notice on June 15th, the termination date would be August 31st. Refer to the Ontario Landlord & Tenant Board site for details.