RentWise Team: A periodic tenancy does not allow a landlord to increase the rent whenever they choose. They must follow the rent-setting rules that apply to the tenancy, including any applicable national rent-control limit, and serve the prescribed written notice—usually at least 90 days. The permitted increase and notice requirements can depend on the property and whether a legal exemption applies. If you believe the increase is invalid, you can seek advice from the RTB or a solicitor; any dispute outcome depends on the individual tenancy facts.