Do I need to worry about QST

QST is Quebec's own sales tax, administered by Revenu Québec rather than the CRA, and it sits alongside GST rather than replacing it. If you are wondering whether it lands on you, the question really splits in two: whether you have enough of a Quebec footprint for QST to apply at all, and, if so, whether you are over the registration line.

The threshold mirrors the federal one. Quebec uses the same $30,000 small-supplier test, measured the same way: worldwide taxable sales, yours plus any associates', over a single calendar quarter or the last four. So a business that has to register federally is often in the same position for QST, and in Quebec the two are commonly registered and filed together.

Where the Quebec footprint comes in. QST generally reaches a business carrying on business in Quebec. Selling into Quebec from elsewhere is its own subject: Revenu Québec runs a separate "specified" registration system aimed at suppliers and digital platforms outside the province, with its own rules. Which system, if any, fits a given seller is not something to eyeball.

Where this becomes your decision. Whether you have a Quebec presence that brings QST into play, and whether you have crossed the threshold, are judgment calls on your specific facts, and the out-of-province rules add a layer on top. Those belong with your accountant. What TALISK_HQ does do is treat QST as a first-class tax beside GST once your book is set up for it, so a Quebec registrant's worksheet reflects both.