Used 2021 GMC Sierra 2500HD for Sale near Illinois

How much does the 2021 GMC Sierra 2500HD cost?

Prices have softened 6.86% compared to this time last year, making it a favorable time to shop this model year.

There are 1,921 listings available, which gives you a solid pool of used trucks to compare.

Is the 2021 GMC Sierra 2500HD a good car?

Yes — the 5/5 user rating points to strong owner satisfaction, and the Sierra 2500HD’s appeal comes from its broad range of trims, body styles, and available upscale features. The overview also shows that you can shop it as a work-focused heavy-duty truck or a more refined pickup with comfort and technology upgrades, depending on what you need. That flexibility makes it a strong fit if you want utility without giving up a more premium feel. Good and great deals account for 35.1% of listings, which gives you some room to shop selectively.

Is the 2021 GMC Sierra 2500HD reliable?

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

The overview points to a truck with broad capability and a premium-leaning identity, but it also highlights known trouble spots such as emissions-related warnings, infotainment lag, rough shifting, electrical glitches, tailgate issues, and trailer brake controller problems. For used buyers, that means reliability can depend heavily on how the truck was maintained and whether those systems have already been addressed.

What should I look for when buying a used 2021 GMC Sierra 2500HD?

Accident-free inventory is solid at 76.2% — always verify the vehicle history report.

You should prioritize a history report first, then focus your inspection on signs of prior damage, warning lights, and any evidence of drivetrain or electrical issues. Pay close attention to how the infotainment system responds, how the transmission shifts, and whether the tailgate and trailer brake systems operate correctly. Condition matters most on a truck like this because expensive repairs can quickly outweigh a good purchase price.

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

This is a moderate market, so you can be selective without expecting deep bargain-bin pricing.

• Deal availability: 35.1% of listings are priced as good or great deals.
• Inventory: There are 1,921 listings available.
• Price trend: Prices have softened 6.86% compared with last year.
• Clean inventory: 76.2% of listings are accident-free.

If you find a listing below $49,307, 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 $49,307 sits slightly below last year's $52,937.

That decline suggests the market has eased, which can help you buy more confidently now, but it also means future resale gains may be limited if prices keep drifting down. If you plan to sell later, the best protection is buying a clean, well-kept example at a sensible price today. Trucks with strong demand and broad appeal tend to hold value better when they’re maintained carefully.

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:

• 35.1% of listings are priced as good or great deals.
• Accident-free inventory is solid at 76.2% — always verify the vehicle history report.
• Price trend: Prices have softened 6.86% compared with last year.
• Owners rate it 5/5 — a strong satisfaction signal.

Consider the 2020 if:

• At $47,867, the 2020 costs less than the current year's $49,307 average.
• It offers a more upscale Denali-focused identity.

Consider the 2022 if:

• At $50,214, the 2022 costs more than the current year's $49,307 average.
• It adds a broader mix of capability and convenience features.

The bottom line: The 2021 is the best all-around pick if you want a strong mix of price movement, inventory depth, and owner satisfaction. If you’re more price-sensitive, the 2020 is the better value path, while the 2022 makes sense if you want a newer truck and are willing to pay a bit more.

How does the 2021 GMC Sierra 2500HD compare to the 2021 Ford F-250 Super Duty?

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

These recommendations are based on CarGurus' proprietary market data from November 3, 2026, CarGurus experts' opinions, and generative AI.