Used 2021 Mercedes-Benz GLS for Sale near Tennessee

How much does the 2021 Mercedes-Benz GLS cost?

Prices have softened 11.12% compared to this time last year, making it a favorable time to shop this model year.

There are 784 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 Mercedes-Benz GLS is positioned as a full-size luxury SUV that emphasizes comfort, upscale presentation, and everyday usefulness. It offers three rows of spacious seating and plenty of cargo space, so it fits you well if you want a large luxury SUV that can handle family duty without giving up refinement.

The main trade-offs are a cramped third row and technology that can be unintuitive. Fuel economy is also poor, so if efficiency matters a lot, this is not the strongest choice.

Only 34.4% of listings are priced as good or great deals, so the market is selective rather than flooded with bargains.

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 comfort and upscale usability, and the expert review reinforces that it delivers a composed, luxury-first experience. The performance notes also point to a hushed ride and a vehicle that feels smaller and easier to manage than its size suggests, which can help reduce day-to-day ownership stress.

The performance content also highlights Mercedes’ EQ Boost 48-volt mild-hybrid system, which supports the engines and helps spool the turbochargers more quickly. That kind of setup suggests a sophisticated powertrain rather than a bare-bones one, and the overall package is aimed at buyers who want refinement as much as capability.

If you buy used, the biggest long-term ownership risk is that this is a complex luxury SUV, so condition and maintenance history matter a lot.

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 multiple powertrain and technology systems. Focus on overall condition, because the GLS is designed to deliver comfort and upscale presentation, and neglected examples can be expensive to bring back to that standard.

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 a more aggressive body, quad-outlet exhaust, and a performance-focused cabin. The GLS 450 is the best-value trim if you want the core luxury experience without stepping up to the pricier V8 models.
• 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 Mercedes’ EQ Boost 48-volt mild-hybrid system, which can add 21 hp and 184 lb-ft 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.
• Infotainment: The GLS uses the MBUX system with a massive touchscreen, a central trackpad controller, Apple CarPlay, Android Auto, and voice control through “Mercedes” or “Hey Mercedes.” The system is designed around large, easy-to-read icons, but it does have 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 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 trim to start with if you want the GLS experience at the lowest entry point. You still get the luxury basics, strong standard tech, and the full-size three-row layout, plus the core comfort features that make the GLS appealing in the first place.
• GLS 580: This trim adds V8 power and a richer feature set, including heated-and-cooled front seats, massaging front seats, illuminated running boards, soft-close doors, and five-zone climate control. It suits you if you want more performance and more luxury without going all the way to the AMG model.
• Mercedes-AMG GLS 63: This is the performance-focused choice, with the most powerful engine, more aggressive styling, and a cabin that leans into sportier presentation. It makes sense if you want the most dramatic version of the GLS and are willing to pay for it.

Standard safety equipment includes Active Brake Assist, blind-spot monitoring, automatic parking assist, a surround-view camera system, and crosswind assist.

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

This looks like a moderate buyer’s market, so you have room to shop carefully rather than rush.

• Deal availability: 34.4% of listings are priced as good or great deals.
• Inventory: There are 784 listings available.
• Price trend: Prices have softened 11.12% compared with last year.
• Clean inventory: 83.3% of listings are accident-free.

If you find a listing below $46,775, 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 $46,775 sits slightly below last year's $52,628.

That price decline suggests the market has already adjusted downward, which can help you as a buyer but may pressure future resale returns if you sell soon. For a future seller, the key takeaway is that the GLS is currently trading below its prior-year level, so holding the vehicle longer may be the better path if you want to recover more value over time.

Strong demand for well-kept luxury SUVs can still support resale, especially when the vehicle presents well and has a clean history. A lower current average can also make the model more attractive to used buyers, which helps keep it moving in the market.

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.

It comes standard with 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. That gives you a broad standard safety package, and available upgrades include lane-keep assist, lane-change assist, adaptive cruise control, a following-distance indicator, and stop-and-go cruise control.

One thing to keep in mind is that some advanced driver-assistance features are optional rather than standard, so you should confirm the exact equipment on any used listing 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:

• 34.4% 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 11.12% compared with last year.
• Owners rate it 4.67/5 — a strong satisfaction signal.
• The 2021 model combines three-row luxury, multiple powertrain choices, and a high-end cabin with a broad standard safety suite.

Consider the 2022 if:

• At $47,197, the 2022 costs more than the current year's $46,775 average.
• Mercedes withdrew most V8 models, leaving only the base six-cylinder GLS 450.

The bottom line: If you want the stronger value proposition, the 2021 is the better starting point because prices have eased and inventory is healthy enough to shop selectively. If you’re focused on the newest nearby version and are fine with a narrower powertrain lineup, the 2022 is worth a look, but price-sensitive buyers will likely find the 2021 more compelling.

These recommendations are based on CarGurus' proprietary market data from September 22, 2026, CarGurus experts' opinions, and generative AI.