Used 2021 Mercedes-Benz GLS for Sale nearBirmingham, AL

How much does the 2021 Mercedes-Benz GLS cost?

Prices have softened 9.36% compared to this time last year, making it a favorable time to shop this model year.

There are 801 listings available, which gives you a meaningful amount of inventory to compare.

If you find a listing below $47,874.80, 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 score 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 its appeal starts with three-row practicality wrapped in a premium cabin. The overview also makes clear that you get spacious seating and useful cargo room, so you can use it as a family hauler without giving up the upscale feel.

The trade-offs are real: the third row is cramped, the technology can be unintuitive, and fuel economy is poor. Even so, the combination of multiple powertrain options, strong performance, and impressive technology makes it a compelling fit if you want a high-end three-row SUV and can live with some compromises.

35.6% of listings are priced as good or great deals, which suggests there are still worthwhile opportunities in the market.

Is the 2021 Mercedes-Benz GLS reliable?

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

The overview points to a model built around comfort, refinement, and practical three-row utility, while the expert review reinforces that it delivers a composed, premium driving experience. The performance notes also show a sophisticated setup with multiple powertrain choices and EQ Boost support across the lineup, which adds to the sense of engineering depth.

The performance content also highlights EQ Boost’s ability to add extra power when needed and help spool the turbochargers more quickly. On the ownership side, that kind of system can make the vehicle feel more polished in daily use, though it also adds complexity compared with a simpler powertrain.

For used buyers, the main long-term risk is that a luxury SUV with this much technology and hardware can be costly to keep in top shape if prior maintenance was neglected.

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

Accident-free inventory is solid at 83.6% — always verify the vehicle history report.

You should still check the history report carefully, because a clean listing percentage does not replace a proper records review. Prioritize a pre-purchase inspection that focuses on the suspension, electronics, and interior condition, since this is a tech-heavy luxury SUV. Pay close attention to how the third row, infotainment controls, and driver-assistance features operate in real-world use.

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 sound system. The GLS 580 adds V8 power plus 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-focused cabin treatment.
• 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 mild-hybrid support.
• 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.
• Infotainment: The GLS uses the MBUX system with a massive touchscreen, a trackpad controller, Apple CarPlay, Android Auto, and voice control through “Mercedes” or “Hey Mercedes.” The digital dash and steering-wheel touch controls add capability, but they also create a learning curve.
• Fuel efficiency: The GLS 450 returns 20 mpg city, 24 highway, and 21 combined. The GLS 63 returns 14 mpg city, 18 highway, and 16 combined. In combined driving, the GLS 63 was observed at 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 best-value choice if you want the core GLS experience with strong standard equipment, including heated front seats, wireless charging, Apple CarPlay, Android Auto, and a Burmester audio system. It gives you the luxury, space, and technology that define the model without pushing into the highest price tiers.
• GLS 580: Choose this if you want more power and a richer feature set, including V8 performance, massaging front seats, soft-close doors, and five-zone climate control. It makes sense if you want the GLS to feel more indulgent and you are willing to pay for it.
• Mercedes-AMG GLS 63: This is the performance-focused version, with the most powerful engine, more aggressive styling, and a cabin that leans into sportier character. It suits you if acceleration and presence matter more than value.

The GLS 450 includes the most approachable standard setup, while the GLS 580 and AMG GLS 63 add more luxury and performance. Safety equipment is generous across the lineup, with additional driver-assistance features available beyond the standard package.

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 with some leverage if you compare listings carefully.

• Deal availability: 35.6% of listings are priced as good or great deals.
• Inventory: There are 801 listings available.
• Price trend: Prices have softened 9.36% compared with last year.
• Clean inventory: 83.6% of listings are accident-free.

If you find a listing below $47,874.80, 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 $48,263 sits slightly below last year's $53,247.

That price movement suggests the market has cooled enough to give you better entry pricing now than a year ago. If you buy well today, you may reduce the risk of overpaying relative to recent market highs.

For a future seller, the softer pricing environment means resale gains may be harder to realize quickly. Still, a well-kept GLS with desirable equipment and strong condition should remain appealing to luxury-SUV shoppers.

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 safety tech includes lane-keep assist, lane-change assist, adaptive cruise control, a following-distance indicator, and stop-and-go cruise control.

That standard equipment list is strong, but you should still check whether a specific used example has the optional driver-assistance features you want. The safety package is broad, yet some of the more advanced convenience features remain optional.

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:

• 35.6% of listings are priced as good or great deals.
• Accident-free inventory is solid at 83.6% — always verify the vehicle history report.
• Price trend: Prices have softened 9.36% compared with last year.
• Owners rate it 4.67/5 — a strong satisfaction signal.
• The 2021 GLS stands out for its luxury-first three-row layout, strong performance options, and impressive technology.

Consider the 2022 if:

• At $48,156, the 2022 costs less than the current year's $48,263 average.
• Mercedes made the 2022 the brand’s flagship SUV with only the base six-cylinder GLS 450 4Matic available at the time.

The bottom line: If you want the broader trim range and the strongest mix of luxury, performance, and technology, the 2021 is the better target. If you are price-sensitive and comfortable with a narrower lineup, the 2022 can be the simpler buy.

These recommendations are based on CarGurus' proprietary market data from September 4, 2026, CarGurus experts' opinions, and generative AI.