When are corporate tax returns due in Quebec? Understand your filing deadlines

If your company is incorporated in Quebec, you're required to file two corporation income tax returns every year: the federal T2 tax return to the Canada Revenue Agency, and the provincial CO-17 to Revenu Québec. But when exactly are corporate tax returns due, and is June 30 always the correct date? The short answer: it depends on the end of your taxation year.

Many business owners don’t fully understand the actual corporate tax filing deadlines. As a result, hundreds of Quebec SMEs receive notices of assessment from Revenu Québec or the CRA, along with penalties and interest, simply because they filed late, often without realizing it. And unlike personal income tax filers, corporate income tax deadlines are strict: there is no automatic extension if the due date falls on a weekend or holiday.

In this article, we’ll explain how to determine your Quebec corporate tax return deadline based on your company’s year-end. We’ll also walk you through key exceptions, tax compliance issues, and how T2inc.ca can help your business file its corporate tax returns on time, reduce your risk of penalties, and meet both federal and provincial income tax obligations.

When are corporate tax returns due in Quebec? Understanding your T2 and CO-17 filing timeline

To file your corporate tax returns in Quebec, everything starts with one key detail: your fiscal year-end. Why? Because this date determines your official filing due date and corporate tax payment deadline, both federally (T2 return to the CRA) and provincially (CO-17 to Revenu Québec).

According to the Canada Revenue Agency, a corporation’s taxation year must align with its fiscal year. That means your business must file a tax return no later than six months after the end of the tax year. This general rule is defined under the Income Tax Act and applies to all incorporated entities across Canada, whether you operate in Quebec, Ontario, or elsewhere.

There are two standard scenarios under Canadian tax deadlines:

• If your fiscal year ends on the last day of a month, your return is due on the last day of the sixth month following that date.
• If your fiscal year ends mid-month (e.g., July 15), your return is due on the same day of the sixth month following (e.g., January 15).

Let’s break it down with real examples to better understand how the corporation income tax deadline is calculated and how to stay compliant with federal and Quebec filing and payment requirements.

If your fiscal year ends on December 31: Quebec and CRA tax return deadlines

If your company’s fiscal year ends on December 31, your corporate tax filing deadline is June 30 of the following year. This applies to both the T2 forms and any required schedules (filed with the CRA) and the CO-17 forms and any required schedules (filed with Revenu Québec).

Example:

• Fiscal year-end: December 31, 2024
• Filing deadline: June 30, 2025

This is the standard rule set by both the CRA and the Government of Quebec: file your corporate tax returns within six months of year-end. But remember, payment deadlines may come sooner, as we’ll explain in a later section.

If your fiscal year ends on another date: applying the 6-month corporate tax rule

If your company does not follow the calendar year, the same six-month rule applies. You have exactly six months from the end of your fiscal year to file your returns.

Here are some common examples:

• Fiscal year ends March 31 → due September 30.
• Fiscal year ends June 30 → due December 31.
• Fiscal year ends October 15 → due April 15.

Don’t rely on calendar logic. Filing deadlines are based on the exact number of days, not the end of the month. And if the deadline falls on a Saturday, it is not automatically extended to the next business day, contrary to what some may think. Filing even one day late can lead to penalties, even if no income was earned.

What are the exceptions from the CRA or Revenu Québec?

While the six-month rule applies in most cases, there are a few special scenarios that can change your filing deadline. Here are two common examples.

First return after incorporation

If you’ve just incorporated your business, you must choose a fiscal year-end that will define your first tax year. This date can be any time within 53 weeks (371 days) from the date of incorporation.

Choosing your fiscal year strategically can help you manage your accounting, reporting, and tax obligations more efficiently. It will also set the schedule for your future returns.

Once your first T2 and CO-17 returns are filed, this fiscal year-end becomes your official tax year. Changing it later requires approval from both the CRA and Revenu Québec. For guidance on selecting your fiscal year-end, read our article on how to choose the right fiscal year.

Deemed year-end: sale, merger or control change

Sometimes, your company must end its fiscal year earlier than expected, even if you didn’t request it. This is called a deemed year-end, and it happens automatically in certain situations, including:

• A change in ownership or control;
• A merger or corporate liquidation;
• A major sale of shares or business assets.

In these cases, your fiscal year is considered to have ended immediately before the transaction. You must then file a short-period return for the interim period, even if the full year hasn't passed.

This can move up your filing deadline and may affect your balance owing or even generate capital gains. These situations require close attention and, ideally, support from a tax professional.

Inactive corporations: file anyway to avoid penalties

At T2inc.ca, we regularly see this scenario: business owners reach out one or two years late, thinking they didn’t have to file because their company had no income or activity. And we get it, this is a common assumption. But unfortunately, it's also a costly one.

Even if your corporation earned no revenue and incurred no expenses, you are still required to file a corporate tax return. Under Canadian tax law, every incorporated business must file, unless it has been formally dissolved.

The good news: at T2inc.ca, we handle late filings all the time, often for multiple years at once. If this is your case, there’s no judgment. We’re here to help you get caught up quickly and painlessly, check out our simple service for inactive corporations.

Important tax dates in Quebec: don’t miss the corporate tax deadlines

Besides your T2 and CO-17 filing deadlines, there are a few other dates that every incorporated business in Quebec should know. These include installment payments, tax balances, and the arrival of your notice of assessment. All of these have a direct impact on your cash flow and compliance.

Installment payment deadlines

Many corporations are required to make quarterly installment payments to both Revenu Québec and the CRA. These payments are based on estimated tax and must be made even before your return is filed. To learn more, read our article covering everything you need to know about corporate tax installment payments in Quebec.

Paying your corporate tax balance

It’s important to understand that filing deadlines and payment deadlines are not the same. You might have six months to file your returns, but that doesn’t mean you have six months to pay. In reality, your tax balance is often due earlier, and missing that payment can result in interest charges and penalties from day one.

In Quebec, most companies must pay Revenu Québec no later than two months after the fiscal year-end. This applies whether your business is active or inactive.

At the federal level, the CRA gives Canadian-Controlled Private Corporations (CCPCs) three months to pay. For all other corporations, the payment deadline is two months.

Notice of assessment in Quebec

After you file your T2 and CO-17 returns, both tax authorities will issue a notice of assessment, one from the CRA and one from Revenu Québec.

This document confirms how much tax is owed, any credits or refunds, or adjustments made. While notices are typically issued within a few weeks, both agencies can review your file up to three or four years later if they deem it necessary.

If you’d like to learn more, check out our article explaining what a notice of assessment is in Quebec and why it matters.

T2inc.ca helps you meet your corporate tax deadlines in Quebec

Meeting your T2 and CO-17 filing deadlines isn’t just about avoiding penalties. It’s about running your business responsibly. Staying on schedule shows that your company is organized, compliant, and financially healthy.

Whether your corporation is active, inactive, or just getting started, it’s essential to know your key corporate tax deadlines to avoid mistakes.

At T2inc.ca, we offer a 100% online, fast and reliable solution to file your federal and Quebec corporate tax returns. Our team includes experienced CPAs and tax specialists who understand the challenges facing entrepreneurs in Quebec. Have questions about your filing deadline? Contact us for a free quote or consultation.