In most cases, a landlord can usually only increase a tenant’s rent by the guideline set each year by the Ministry of Municipal Affairs and Housing. Rental units first occupied for residential purposes after November 15, 2018 are exempt from the rules that limit rent increases to the guideline amount. Landlords of these units must still serve a notice of rent increase 90 days in advance with a Landlord and Tenant Board approved form and they can only increase the rent once every 12 months, but there is no limit on the amount of the rent increase. Please visit the Ontario Landlord & Tenant site for more information.