Used 2021 Mercedes-Benz GLS for Sale near Illinois

How much does the 2021 Mercedes-Benz GLS cost?

Prices have softened 10.40% compared to this time last year, making it a favorable time to shop this model year.

There are 809 listings available, which suggests a healthy amount of inventory to compare. If you find a listing below $47,738.73, that's toward the low end of the year-round range and worth acting on quickly.

Is the 2021 Mercedes-Benz GLS a good car?

Yes — the 4.67/5 user rating points to strong owner satisfaction, and the expert rating is 8.33/10. The model scores 9/10 across Look and feel, Performance, Technology, and Safety.

The 2021 GLS is positioned as a luxury-first full-size SUV, and it backs that up with three-row practicality, a premium cabin, and a strong emphasis on comfort and refinement. It also brings surprising performance and impressive technology, so you get more than just a plush family hauler.

The trade-offs are real: the third row is cramped, and the technology can be unintuitive. That means you should value the GLS most if you want a high-end, three-row SUV and can live with some usability compromises.

With 28.9% of listings marked as good or great deals, you have 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 presented as a comfort- and refinement-focused luxury SUV, and its expert evaluation reinforces that it delivers a premium experience with strong performance and a well-appointed cabin. The available powertrains and the overall upscale execution suggest a vehicle built to feel substantial over time.

Its performance hardware and luxury features point to a sophisticated ownership experience, but the technology’s complexity means you should pay close attention to how well everything works on a used example. For used buyers, the biggest long-term risk is buying one with neglected electronics or deferred maintenance.

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

Accident-free inventory is solid at 83.8% — always verify the vehicle history report.

You should start with a history report and then prioritize a thorough inspection of the cabin electronics, driver-assistance features, and any signs of wear in the third row. Because the GLS is a luxury SUV with a lot of technology, condition matters as much as mileage. Make sure the vehicle’s equipment works as intended and that the interior shows the kind of care you’d expect at this price point.

Key things to evaluate:

• Trim level: The GLS is available in three levels: GLS 450, GLS 580, and the Mercedes-AMG GLS 63 performance model. 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, heated-and-cooled front seats, massaging front seats, illuminated running boards, soft-close doors, and five-zone automatic climate control. The AMG GLS 63 adds more aggressive bodywork, a quad-outlet exhaust, and a performance-inspired interior. The GLS 450 is the value-oriented starting point, while the GLS 580 is the best fit if you want more luxury hardware without going all the way to AMG pricing.
• Powertrain: The GLS 450 uses a twin-turbocharged 3.0-liter inline-six with 362 horsepower and 369 pound-feet of torque. The GLS 580 uses a twin-turbocharged 4.0-liter V8 with 483 hp and 516 lb-ft. The AMG GLS 63 uses a hand-crafted 4.0-liter twin-turbo V8 with 603 hp and 627 lb-ft. All engines include EQ Boost 48-volt mild-hybrid assistance, and the setup can add extra power when needed.
• Safety package: Standard equipment includes Active Brake Assist, forward-collision avoidance, rain-sensing wipers, blind-spot monitoring, automatic high beams, automatic parking assist, a surround-view camera system, a driver-drowsiness monitor, and crosswind assist. Available features include lane-keep assist, lane-change assist, adaptive cruise control, a following-distance indicator, and stop-and-go cruise control. Some of those driver-assistance features are optional rather than standard.
• Infotainment: The GLS uses the MBUX system with a massive touch screen, a central controller, Apple CarPlay, Android Auto, and voice control. It also has a fully digital instrument panel and touch-sensitive steering-wheel controls. The system is advanced, but it can take time to learn.
• Fuel efficiency: The GLS 450 returns 20 mpg city, 24 highway, 21 combined. The GLS 63 returns 14 mpg city, 18 highway, 16 combined. In combined driving, the GLS 63 averaged 15.3 mpg.

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 most accessible entry into the GLS lineup. It already brings a long list of standard luxury and tech features, including heated front seats, wireless charging, Apple CarPlay, Android Auto, and the Burmester audio system. It is the best-value trim for most shoppers because it delivers the core GLS experience without the higher cost of the V8 models.
• GLS 580: This trim is the right step up if you want more power and more comfort-focused equipment. It adds a V8 engine, heated-and-cooled front seats, massaging front seats, illuminated running boards, soft-close doors, and five-zone climate control. Choose this one if you want a more indulgent luxury SUV and are willing to pay for it.
• Mercedes-AMG GLS 63: This is the performance-focused choice, with the most powerful engine, more aggressive styling, and a sportier cabin treatment. It suits you best if you want the quickest and most dramatic version of the GLS rather than the most practical one.

Standard safety equipment is strong across the lineup, while some advanced driver-assistance features remain available rather than standard.

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

This is a moderate market for selective buyers, so it makes sense to shop carefully and compare listings.

• Deal availability: 28.9% of listings are priced as good or great deals.
• Inventory: There are 809 listings available.
• Price trend: Prices have softened 10.40% compared with last year.
• Clean inventory: 83.8% of listings are accident-free.

If you find a listing below $47,738.73, 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 $47,685 sits slightly below last year's $53,219.

That price movement suggests the market has cooled, which can help you buy more favorably now but may also mean slower appreciation if you plan to sell later. For a future seller, the softer pricing trend means you should expect more competition from similarly priced listings. Well-kept examples should still stand out, especially if they present cleanly and have desirable equipment.

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?

It earns a 9/10 safety score from our experts.

The GLS comes standard with Active Brake Assist, forward-collision avoidance, rain-sensing wipers, blind-spot monitoring, automatic high beams, automatic parking assist, a surround-view camera system, a driver-drowsiness monitor, and crosswind assist. Available driver-assistance features include lane-keep assist, lane-change assist, adaptive cruise control, a following-distance indicator, and stop-and-go cruise control.

That gives you a strong standard safety foundation, but some of the more advanced assistance features are still optional. If safety tech is a priority, you should confirm exactly which systems are installed on the used example you’re considering.

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:

• 28.9% of listings are priced as good or great deals.
• Accident-free inventory is solid at 83.8% — always verify the vehicle history report.
• Price trend: Prices have softened 10.40% compared with last year.
• Owners rate it 4.67/5 — a strong satisfaction signal.
• The 2021 GLS combines three-row luxury, strong performance, and impressive technology.

Consider the 2022 if:

• At $48,550, the 2022 costs more than the current year's $47,685 average.
• Mercedes narrowed the lineup to the base six-cylinder GLS 450 4Matic.

The bottom line: If you want the better value, the 2021 is the smarter starting point because it offers a lower average price and broader trim variety. If you prefer a simpler lineup and are focused on the base six-cylinder model, the 2022 is worth a look, but you’ll pay more for it.

These recommendations are based on CarGurus' proprietary market data from August 28, 2026, CarGurus experts' opinions, and generative AI.