If you own property on the Island of Montreal, you owe the Montreal school tax every year, whether or not you have children in school. The bill comes from a single collection body, the Comité de gestion de la taxe scolaire de l’île de Montréal (CGTSIM), and for the 2025-2026 year it is calculated at 0.08423% of your property’s standardized assessment value, with the first $25,000 of value exempt.1Comité de gestion de la taxe scolaire de l’île de Montréal. School tax payment2Western Quebec School Board. School Taxes
Who Owes the Tax
The obligation is universal. Every owner of taxable property on the island pays, regardless of whether the household supports a French-language service centre or an English-language board, whether there are children in the family, or whether those children attend public school. The Education Act makes it a property-based tax, not a service fee.1Comité de gestion de la taxe scolaire de l’île de Montréal. School tax payment
The CGTSIM bills the owner listed on the roll when it issues its annual notices after July 1. If the property changes hands during the year, the notary handling the sale usually prorates the tax between buyer and seller at closing. The CGTSIM itself deals only with the registered owner.3CGTSIM. Collection services
How Your Bill Is Calculated
Quebec sets a single school tax rate for the whole province by government decree each year. For 2025-2026, that rate is 0.08423%, and it applies identically to residential, commercial, and industrial properties.2Western Quebec School Board. School Taxes
The rate is not applied to the raw figure on your municipal assessment roll. The province multiplies that figure by a comparative factor set for your municipality, producing what is called the standardized assessment. For 2026, Montreal’s comparative factor is 1.00, so the standardized value equals the roll value.4Ville de Montréal. How property transfer duties are calculated
The first $25,000 of standardized value is exempt under the Education Act, and the exemption is applied automatically. On a property standardized at $500,000, tax is owed on $475,000, which at the current rate comes to roughly $400 for the year.
When Payment Is Due
Bills under $300 are due in a single payment. Bills of $300 or more can be split into two installments. The first is due on the 31st day after the bill is mailed; the second is due on the 121st day after mailing.3CGTSIM. Collection services
For the 2025-2026 cycle, the calendar dates were:
- First installment: August 4, 2025
- Second installment: October 31, 2025
Exact dates for each new year are posted on the CGTSIM website after bills go out in July. If your bill sits close to the $300 line, choosing the two-installment option gives you three extra months on half the balance at no cost.1Comité de gestion de la taxe scolaire de l’île de Montréal. School tax payment
How to Pay and Find Your Bill
Paper bills are mailed after July 1. The fastest way to access your account, especially if the bill was misplaced or never arrived, is the CGTSIM’s secure online portal (TFP Internet), where you can look up your file by property address or cadastral lot number, view your balance, and download a copy of your bill.1Comité de gestion de la taxe scolaire de l’île de Montréal. School tax payment
Payment options include online banking at most major financial institutions, in person at a bank teller, or by mailing a cheque or money order with the detachable stub. For any electronic payment, you need the 20-digit reference number printed in the upper-right corner of the bill. Without it, your bank cannot route the payment to the correct property file.1Comité de gestion de la taxe scolaire de l’île de Montréal. School tax payment
If You Pay Late
Interest starts accruing daily the moment you miss a deadline. There is no grace period. For 2025-2026, the rate is 8.00%, set under the Tax Administration Act and updated annually. It applies to any unpaid balance, including the second installment if you paid the first on time and missed the second.3CGTSIM. Collection services
If You Never Pay
Unpaid school tax compounds and eventually attaches to the property itself. After taxes remain unpaid for roughly two to three years, a tax arrears certificate can be registered against the title. That opens a redemption period of about one year to clear the original tax, accumulated interest, and administrative costs. If the balance is still unpaid at the end of that window, the property can be put up for public sale at the cancellation price, covering all back taxes, interest, and penalties. This is the same forced-sale mechanism that applies to unpaid municipal taxes in Quebec.
Disputing the Bill
The rate is set provincially and the calculation is mechanical, so there is little room to challenge the tax itself. The real lever is the underlying property assessment. If you believe your municipal assessment is too high, you can file a review request with your municipality’s assessment office during the designated revision period, which typically opens when a new three-year assessment roll takes effect. Because the CGTSIM draws its figures from the same municipal roll, a successful reduction in assessed value lowers your school tax automatically. Contact the CGTSIM directly for billing errors, such as a bill sent to the wrong owner or an exemption that was not applied.