Used 2021 GMC Sierra 1500 for Sale near Thornhill, ON

How much does the 2021 GMC Sierra 1500 cost?

Prices have softened 13.37% compared to this time last year, making it a favourable time to shop this model year.

There are 606 listings available, which suggests you have a decent amount of inventory to compare.

Is the 2021 GMC Sierra 1500 a good car?

Yes — owners rate it 4.9/5, and our experts give it 5.7/10. The standout strength is Performance at 9/10.

Owners consistently praise the luxurious features, exceptional engine performance, advanced technology, and comfortable interior. For you, that means the Sierra makes the most sense if you want a full-size pickup that feels more upscale than purely utilitarian. The overview also points to a familiar truck foundation with distinctive styling and unique touches, including an optional carbon-fibre composite cargo bed.

The market shows 32.3% of listings as good or great deals, which gives you some room to shop selectively.

Is the 2021 GMC Sierra 1500 reliable?

Owners rate it 4.9/5, a strong signal of long-term satisfaction.

User feedback highlights a dependable-feeling ownership experience, with many owners describing the truck as a strong-value, trouble-free choice that they can count on. The expert assessment also points to a powertrain that delivers its torque smoothly and a 10-speed automatic that chooses gears well, which supports confidence in day-to-day use.

For used buyers, the main long-term ownership risk is that some desirable features are tied to extra packages, so you should verify equipment carefully before you buy.

What should I look for when buying a used 2021 GMC Sierra 1500?

Key things to evaluate:

• Trim level: The Denali trim level is the upscale choice, while the AT4 adds an off-road-ready setup with a suspension lift, skid plates, a locking rear differential, and unique design details. The base truck can feel sparse, so check whether the features you want are included or bundled into extra packages.
• Powertrain: The Duramax 3.0-litre turbodiesel six-cylinder is the standout engine here, with strong torque and a 10-speed automatic transmission. It also supports easy switching between rear-wheel drive and four-wheel drive modes.
• Safety package: Forward collision warning, front pedestrian braking, and automatic emergency braking are available, while blind-spot warning and rear cross-traffic warning come on Denali and are optional on other trims. Lane-departure warning, lane-keeping assistance, and a Safety Alert Seat are also available depending on trim.
• Infotainment: Look for the 7-inch or 8-inch touchscreen, wireless Apple CarPlay and Android Auto, Bluetooth, SiriusXM satellite radio, and the 4G LTE WiFi hotspot. The available technology package adds a surround-view camera, trailer- and bed-view cameras, a rear camera mirror, a 15-inch head-up display, and an 8-inch driver information display.
• Fuel efficiency: The Duramax diesel is rated at 9.1 L/100 km in combined driving, and the test truck averaged 11.1 L/100 km in mixed conditions.

Which 2021 GMC Sierra 1500 trim should I buy?

The 2021 GMC Sierra 1500 is offered in 2 trim levels: Elevation and AT4.

Here's the short version:

• Elevation: This is the best-value choice if you want a custom appearance and enough flexibility to keep the price in check while still adding useful options. It is the trim most buyers should start with if they want to avoid the Sierra’s tendency to climb quickly in price.
• AT4: Choose this if you want the more rugged, off-road-focused personality. It adds the lifted suspension, skid plates, locking rear differential, and other trail-ready details that make it the more capable and distinctive pick.

Safety-package availability varies by trim, so confirm which driver-assistance features are included before you commit.

Is now a good time to buy a used 2021 GMC Sierra 1500?

This is a moderate market for selective buyers, so it pays to compare listings carefully and move quickly on strong examples.

• Deal availability: 32.3% of listings are priced as good or great deals.
• Inventory: There are 606 listings available.
• Price trend: Prices have softened 13.37% compared with last year.

If you find a listing below $39,069 CAD, that's toward the low end of the year-round range and worth acting on quickly.

What is the 2021 GMC Sierra 1500's resale value?

The current average of $39,069 CAD sits slightly below last year's $45,097 CAD.

That price drop suggests the market has become more favourable for buyers, but it also means future sellers may face more competition if prices stay soft. If you buy well now, you may have less downside risk than someone who purchased when values were higher. The Sierra’s broad appeal and premium positioning can still support demand, especially for well-equipped examples.

Vehicles with strong owner satisfaction ratings, like this model year's 4.9/5, tend to retain buyer demand, which supports resale value over time.

Is the 2021 GMC Sierra 1500 safe?

The 2021 GMC Sierra 1500 earns four-star ratings in frontal crash and five-star ratings in all other NHTSA tests.

It earns a 4/10 safety score from our experts.

GMC offers forward collision warning, front pedestrian braking, and automatic emergency braking, though these are not standard across the lineup. Blind-spot warning and rear cross-traffic warning are included on Denali and optional on other trims, while lane-departure warning, lane-keeping assistance, and a Safety Alert Seat are also available depending on trim. Adaptive cruise control is optional on SLT, AT4, and Denali.

The main caveat is that the Sierra’s crash-test results are mixed, with IIHS calling out a Marginal result for the front passenger in the small-overlap frontal test, a Poor headlight rating, and Marginal LATCH accessibility.

Should I buy a 2021 GMC Sierra 1500 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:

• 32.3% of listings are priced as good or great deals.
• Price trend: Prices have softened 13.37% compared with last year.
• Owners rate it 4.9/5 — a strong satisfaction signal.
• This year stands out for its upscale styling, strong engine performance, and useful tech.

Consider the 2022 if:

• At $46,566 CAD, the 2022 costs more than the current year's $39,069 CAD average.
• It brings a major makeover with bolder styling, a more lavish interior, standard high-end technology, and added utility.

The bottom line: Choose the 2021 if you want a lower entry price and strong owner satisfaction. Consider the 2022 if you’re willing to pay more for a more thoroughly updated truck.

How does the 2021 GMC Sierra 1500 compare to the 2021 Ford F-150?

Our experts score the 2021 GMC Sierra 1500 5.7/10 and the 2021 Ford F-150 7.8/10. The Ford is the stronger overall pick, with better expert scoring, lower average used pricing, and more listings to shop from. The Sierra still appeals if you want the more upscale GMC presentation and strong owner satisfaction, but it trails on value and breadth of inventory.

Read our full side-by-side expert comparison here.

These recommendations are based on CarGurus' proprietary market data from October 21, 2026, CarGurus experts' opinions, and generative AI.