Used 2021 Mercedes-Benz GLS for SaleNationwide

How much does the 2021 Mercedes-Benz GLS cost?

Prices have softened 20.89% compared to this time last year, making it a favourable time to shop this model year.

There are 54 listings available, which suggests you should have a reasonable amount of inventory to compare.

Is the 2021 Mercedes-Benz GLS a good car?

Yes — 4.67/5 is a strong user rating for this model year, and the expert rating is 8.33/10. The model scores 9/10 across Look and feel, Performance, Technology, and Safety.

The 2021 Mercedes-Benz GLS is positioned as the S-Class of SUVs, so you get three rows of spacious seating, a strong comfort focus, and a clear luxury-first approach. It also brings surprising performance for a full-size SUV, which helps it stand out if you want something that feels especially upscale without giving up practicality.

The market also shows 31.5% of listings as good or great deals, which gives you some room to shop selectively.

Is the 2021 Mercedes-Benz GLS reliable?

Owners rate it 4.67/5, a strong signal of long-term satisfaction.

The GLS is described as a highly comfortable, luxury-focused SUV with a holistic approach to refinement, and the expert evaluation highlights strong fit-and-finish. Its powertrains also use EQ Boost mild-hybrid assistance, which supports smooth operation and adds extra output when needed.

The six-cylinder GLS 450 is the most efficient version, and that can help reduce day-to-day ownership strain if you plan to drive it often. For used buyers, the main long-term risk is that this is a high-end SUV with high-end running costs, so condition and maintenance history matter.

What should I look for when buying a used 2021 Mercedes-Benz GLS?

Key things to evaluate:

• Trim level: The GLS 450 includes remote keyless entry, remote start, nine USB ports, dual-zone automatic climate control, heated front seats, a power liftgate, wireless device charging, Apple CarPlay, Android Auto, satellite radio, and a 13-speaker Burmester premium sound system. The GLS 580 adds V8 power and more content, while the AMG GLS 63 brings more aggressive bodywork, a quad-outlet exhaust, and a performance-focused cabin. The GLS 450 is the best-value starting point if you want the core luxury and practicality without moving up in price.
• Powertrain: The GLS 450 uses a twin-turbocharged 3.0-litre inline-six with 362 horsepower and 369 pound-feet of torque. The GLS 580 uses a twin-turbocharged 4.0-litre V8 with 483 hp and 516 lb-ft, while the AMG GLS 63 uses a hand-crafted 4.0-litre twin-turbo V8 with 603 hp and 627 lb-ft. All engines include EQ Boost 48-volt mild-hybrid assistance.
• Safety package: Standard equipment includes Active Brake Assist, rain-sensing wipers, automatic high beams, automatic parking assist, a driver-drowsiness monitor, crosswind assist, front-and-side-impact airbags, traction control, self-tensioning seatbelts, and a tire-pressure monitoring system. Available features include lane-change assist, adaptive cruise control, blind spot monitoring, rear cross-traffic alert, a following-distance indicator, and stop-and-go cruise control.
• Infotainment: The GLS uses the MBUX system with a massive touch screen, a trackpad controller, Apple CarPlay, Android Auto, and voice control. The system is designed around large, easy-to-read icons and a fully digital instrument panel.
• Fuel efficiency: The GLS 450 uses 12.0 litres per 100 kilometres in city driving, 9.8 on the highway, and 11.0 combined. The GLS 63 uses 16.3 L/100 km city, 12.9 highway, and 14.8 combined.

Which 2021 Mercedes-Benz GLS trim should I buy?

The 2021 Mercedes-Benz GLS is offered in 3 trim levels: GLS 450, GLS 580, and Mercedes-AMG GLS 63.

Here's the short version:

• GLS 450: This is the trim to start with if you want the core GLS experience at the lowest entry point. You still get the luxury basics, the full-size three-row layout, and the standard tech and safety equipment that define the model.
• GLS 580: This trim adds V8 power and more upscale content, so it suits you if you want stronger performance and are willing to pay more for it.
• Mercedes-AMG GLS 63: This is the performance-focused choice, with the most powerful engine, more aggressive styling, and a sportier driving character.

The GLS comes standard with a host of driver-assistance features, and additional safety tech is available on higher trims and through options.

Is now a good time to buy a used 2021 Mercedes-Benz GLS?

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

• Deal availability: 31.5% of listings are priced as good or great deals.
• Inventory: There are 54 listings available.
• Price trend: Prices have softened 20.89% compared with last year.

If you find a listing below $65,655 CAD, that's toward the low end of the year-round range and worth acting on quickly.

What is the 2021 Mercedes-Benz GLS's resale value?

The current average of $67,327 CAD sits slightly below last year's $85,111 CAD.

That price drop suggests the market has already adjusted downward, which can help you buy more confidently now. For a future seller, it also means resale value may depend heavily on how well your vehicle is equipped and maintained, since buyers in this segment tend to compare condition closely. If demand stays steady, a well-kept GLS should still appeal to shoppers looking for a full-size luxury SUV with strong presence and three-row practicality.

Vehicles with strong owner satisfaction ratings, like this model year's 4.67/5, tend to retain buyer demand, which supports resale value over time.

Is the 2021 Mercedes-Benz GLS safe?

The 2021 Mercedes-Benz GLS earns a 9/10 safety score from our experts.

It comes standard with Active Brake Assist, rain-sensing wipers, automatic high beams, automatic parking assist, a driver-drowsiness monitor, crosswind assist, and a full array of front-and-side-impact airbags. Available driver-assistance features include lane-change assist, adaptive cruise control, blind spot monitoring, rear cross-traffic alert, a following-distance indicator, and stop-and-go cruise control.

That gives you a strong standard safety foundation, with more advanced assistance features available if you choose a better-equipped trim or option package.

Should I buy a 2021 Mercedes-Benz GLS 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:

• 31.5% of listings are priced as good or great deals.
• Price trend: Prices have softened 20.89% compared with last year.
• Owners rate it 4.67/5 — a strong satisfaction signal.
• It delivers three rows of spacious seating, strong comfort, and surprising performance in a full-size luxury SUV.

Consider the 2022 if:

• At $67,849 CAD, the 2022 costs more than the current year's $67,327 CAD average.
• It continues the current-generation GLS with expected specifications close to 2021.

The bottom line: If you want the better value, the 2021 is the smarter place to start because pricing has eased and inventory is available. If you prefer to stay closer to the newest model year and are comfortable paying a bit more, the 2022 is the cleaner alternative.

These recommendations are based on CarGurus' proprietary market data from September 15, 2026, CarGurus experts' opinions, and generative AI.