Used 2021 Mercedes-Benz GLS for Sale near Alabama

How much does the 2021 Mercedes-Benz GLS cost?

Prices have softened 9.94% compared to this time last year, making it a favorable time to shop this model year.

There are 777 listings available, which gives you a meaningful amount of inventory to compare.

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 full-size luxury SUV with three rows of spacious seating, a comfort-first character, and plenty of cargo space for larger loads. It also stands out for its multiple powertrain options and upscale presentation, which help it feel like a luxury flagship rather than just a family hauler.

The trade-offs are real: the third row is cramped, the technology can be unintuitive, and fuel economy is poor. If you want a large SUV that leans hard into refinement, capability, and passenger comfort, those compromises may be acceptable.

Only 37.2% of listings are priced as good or great deals, so the market is selective rather than deeply discounted.

Is the 2021 Mercedes-Benz GLS reliable?

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

The GLS is built around a comfort-focused, upscale formula, and the expert review emphasizes its composed ride, strong performance, and high-end fit and finish. It also highlights a hushed cabin and a luxury-first driving experience, which are encouraging signs if you plan to keep the vehicle for the long haul.

The performance notes point to a refined powertrain lineup and a mild-hybrid system that supports the engines when needed. That kind of setup can help the SUV feel smooth and responsive in everyday driving.

If you buy used, the biggest long-term ownership risk is that a complex luxury SUV can be expensive to live with if prior maintenance or condition has been neglected.

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

Accident-free inventory is solid at 83.3% — always verify the vehicle history report.

You should still check the history report carefully and prioritize a pre-purchase inspection, especially on a luxury SUV with advanced technology and multiple powertrain choices. Focus on cabin condition, electronics, and how well the vehicle has been maintained, since those areas matter most on a premium three-row model.

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, five-zone automatic climate control, and 21-inch wheels. The AMG GLS 63 adds more aggressive bodywork, a quad-outlet exhaust, a chrome slotted grille, and a performance-inspired flat-bottomed steering wheel.
• 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 come with Mercedes’ EQ Boost 48-volt mild-hybrid system.
• Safety package: Standard safety 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.
• Infotainment: The GLS uses the MBUX system with a massive touch screen, a central controller, Apple CarPlay, Android Auto, and voice control through “Mercedes” or “Hey Mercedes.” The display is controlled by touch-sensitive pads on the steering wheel, and the system has a learning curve.
• 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 test vehicle 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 most accessible entry point and still comes well equipped with remote keyless entry, remote start, heated front seats, wireless charging, Apple CarPlay, Android Auto, and the Burmester audio system. It is the best-value trim if you want the GLS experience without paying for the V8 upgrades.
• GLS 580: This trim adds V8 power plus comfort upgrades like heated-and-cooled front seats, massaging front seats, soft-close doors, illuminated running boards, and five-zone climate control. It makes sense if you want a more luxurious feel and stronger performance.
• 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 if you want the most dramatic version of the GLS and are willing to pay for it.

The GLS 450 includes the broadest standard equipment, while the available safety tech expands further with lane-keep assist, lane-change assist, adaptive cruise control, and stop-and-go cruise control.

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

This looks like a moderate, selective buyer’s market, so you should shop carefully and move quickly on strong listings.

• Deal availability: 37.2% of listings are priced as good or great deals.
• Inventory: There are 777 listings available.
• Price trend: Prices have softened 9.94% compared with last year.
• Clean inventory: 83.3% of listings are accident-free.

If you find a listing below $47,795, 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 $47,795 sits slightly below last year's $53,071.

That decline suggests the market has already adjusted downward, which can help you as a buyer but may pressure resale if you plan to sell soon. For a future seller, the key takeaway is that pricing momentum is softer than it was a year ago, so holding out for a premium may be harder unless your vehicle is especially clean and well equipped.

The current range also shows that buyers have options, which can keep resale values competitive rather than inflated. Well-kept examples with desirable equipment should still attract attention, but condition will matter a lot.

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

Standard driver-assistance equipment includes Active Brake Assist, forward-collision avoidance, blind-spot monitoring, automatic high beams, automatic parking assist, a surround-view camera system, a driver-drowsiness monitor, and crosswind assist. Available upgrades 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 safety foundation even before optional tech is added. If you are comparing trims, the main gap is not basic safety coverage but access to the more advanced driver-assistance features.

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:

• 37.2% of listings are priced as good or great deals.
• Accident-free inventory is solid at 83.3% — always verify the vehicle history report.
• Price trend: Prices have softened 9.94% compared with last year.
• Owners rate it 4.67/5 — a strong satisfaction signal.
• The 2021 model stands out for its three-row luxury focus, multiple powertrain options, and upscale presentation.

Consider the 2022 if:

• At $47,558, the 2022 costs less than the current year's $47,795 average.
• Mercedes withdrew most V8 models, leaving only the base six-cylinder GLS 450 4Matic.

The bottom line: If you want the broader 2021 lineup with more powertrain choice and a strong mix of luxury and capability, the 2021 is the better target. If you are price-sensitive and comfortable with the base six-cylinder setup, the 2022 can be the simpler, slightly cheaper path.

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