Used 2021 GMC Sierra 2500HD for Sale near Thornhill, ON

How much does the 2021 GMC Sierra 2500HD cost?

Prices have held steady compared to this time last year, signaling a stable and predictable market for this model year.

There are 78 listings available, which gives you a modest amount of choice without making the market feel crowded.

Is the 2021 GMC Sierra 2500HD a good car?

Yes — it earns a user rating of 5/5, which points to strong owner satisfaction. The 2021 Sierra 2500HD stands out as a heavy-duty pickup that leans more upscale than many rivals, and that broader range of trim levels and upscale options helps it appeal if you want serious truck capability without giving up comfort. It also fits GMC’s “Professional Grade” image, so you get a work-capable three-quarter-ton pickup with a more premium feel. With 34.6% of listings marked as good or great deals, you still have some room to shop carefully.

Is the 2021 GMC Sierra 2500HD reliable?

Owners rate it 5/5, a strong signal of long-term satisfaction.

The 2021 Sierra 2500HD is described as having a long list of reported problems, including check engine lights, infotainment sluggishness, rough or delayed shifts, electrical glitches, MultiPro tailgate faults, and faulty trailer brake controllers. That means you should pay close attention to service history and how the truck behaves on a test drive. For used buyers, the main long-term ownership risk is ending up with a truck that looks capable on paper but needs costly repairs or troubleshooting after purchase.

Is now a good time to buy a used 2021 GMC Sierra 2500HD?

This looks like a moderate, selective buyer’s market, so you can shop patiently and still find worthwhile listings.

• Deal availability: 34.6% of listings are priced as good or great deals.
• Inventory: There are 78 listings available.
• Price trend: Prices have held steady compared with last year.

If you find a listing below $56,247 CAD, that's toward the low end of the year-round range and worth acting on quickly.

What is the 2021 GMC Sierra 2500HD's resale value?

The current average of $58,789 CAD sits slightly above last year's $58,301 CAD.

That small increase suggests the market has stayed resilient rather than softening. For a future seller, that can be a positive sign because it points to steady buyer interest and less pressure to discount heavily. The truck’s premium positioning and broad trim range can also help support demand, especially for well-equipped examples.

Vehicles with strong owner satisfaction ratings, like this model year's 5/5, tend to retain buyer demand, which supports resale value over time.

Should I buy a 2021 GMC Sierra 2500HD or consider a different year?

If you're weighing the 2021 against nearby model years, here's how to think about it:

Choose the 2021 if:

• 34.6% of listings are priced as good or great deals.
• Price trend: Prices have held steady compared with last year.
• Owners rate it 5/5 — a strong satisfaction signal.

Consider the 2022 if:

• At $60,985 CAD, the 2022 costs more than the current year's $58,789 CAD average.
• It broadens appeal with work, off-road, infotainment, trailering, and safety focus.

The bottom line: If you want the better value today, the 2021 is the stronger starting point because pricing is stable and there are still some good deals in the market. If you are willing to pay more for a newer model year and a broader feature focus, the 2022 is the better secondary path. For price-sensitive buyers, the 2021 makes the most sense when you can find one near the low end of the range.

These recommendations are based on CarGurus' proprietary market data from October 13, 2026, CarGurus experts' opinions, and generative AI.