QST Registration in Quebec: Why Revenu Québec Is a Second Tax Agency

Every province charges a version of sales tax on top of the federal GST, and for most of the country that’s a fact you note once and move on. Quebec QST and Revenu Québec registration is the exception — it becomes an actual administrative task rather than a line on an invoice, and it catches newcomers running a small business or side income who assumed sales tax meant the same paperwork everywhere.

The rate itself

Start with the arithmetic: how much is QST in Quebec, and what does it add at the till? Quebec’s combined sales tax comes to 14.975% — the federal 5% GST plus a provincial QST of 9.975%, one of the higher combined rates in the country. That’s added at the till rather than folded into the shelf price the way South African VAT is; a $20 item in Quebec costs closer to $23 once both taxes land on it.

Why there’s a second agency at all

Quebec is unusual in Canada for administering its provincial sales tax through its own agency, Revenu Québec, rather than folding it into the federal system the way most other provinces do with a harmonised or provincial sales tax collected alongside GST. Whether you have to register with Revenu Québec separately is exactly the right question to ask if you’re setting up a business with any Quebec presence — but registration thresholds, what counts as carrying on business in the province, and how the two agencies interact are specific rules this post doesn’t have verified figures for. Confirm directly with Revenu Québec or an accountant rather than assuming either way.

One return or two

Ask an accountant early: do you file GST and QST on one return, or two? The answer depends on your registration setup and business structure, and it’s a mechanical detail worth getting right from day one rather than fixing after your first filing period. A Canadian accountant answers this definitively for your specific business in a short conversation; a general post shouldn’t guess at it.

The small supplier question

Most Canadian sales tax systems carve out a small supplier exemption below a revenue threshold, which raises the obvious follow-up: does a small supplier rule apply to QST as well? It’s a real distinction that changes whether a small side business needs to register at all. Confirm it against current Revenu Québec guidance instead of assuming it works the same way GST small-supplier rules do elsewhere.

What this actually means for a newcomer

If your work or business touches Quebec at all — a client based there, inventory shipped there, services delivered there — treat it as a second tax jurisdiction inside Canada rather than an extension of whatever GST or HST setup you already have. That’s the mental model worth arriving with, even before you know every threshold and form number.

This is squarely accountant territory rather than something to piece together from general guidance, and getting it wrong has real cost in penalties and back-filing. A Canadian accountant with Quebec experience, engaged early, is worth more here than any amount of research. Cape2Canada’s guide on what the move really costs is a reasonable place to start budgeting for that kind of professional help before you need it urgently.