Used 2021 Mercedes-Benz GLS for Sale near Washington

How much does the 2021 Mercedes-Benz GLS cost?

Prices have softened 9.14% compared to this time last year, making it a favorable time to shop this model year.

There are 864 listings available, which suggests you should have a workable selection to compare.

Is the 2021 Mercedes-Benz GLS a good car?

Yes — the 2021 Mercedes-Benz GLS earns a 4.7/5 user rating and an 8.3/10 expert rating. The model scores 9/10 across Look and feel, Performance, Technology, and Safety.

The GLS is positioned as a full-size luxury SUV that aims to bring S-Class-style refinement to a three-row format, and the test-drive summary says it delivers on that idea with a higher standard of luxury and impressive performance. It also stands out for spacious seating and cargo flexibility, which makes it appealing if you want a premium family hauler that can handle groceries, weekend bags, and larger cargo.

The trade-offs are clear: the third row is cramped, the technology can be unintuitive, and fuel economy is poor. If you value luxury, capability, and a flagship feel more than maximum efficiency or the most generous third-row space, it fits the brief well.

Only 33.2% 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 4.7/5, a strong signal of long-term satisfaction.

The GLS is described as a comfortable, well-finished luxury SUV with a strong emphasis on refinement, and the expert summary reinforces that it delivers a polished ride and a high-end cabin experience. Its performance notes also point to a composed, capable drivetrain lineup, which supports confidence in everyday use.

The performance content also highlights Mercedes’ EQ Boost 48-volt mild-hybrid system, which adds extra output when needed and helps spool the turbochargers more quickly. That kind of engineering can support smooth operation over time, especially when you keep up with routine maintenance.

If you buy used, the main long-term risk is that a complex luxury SUV can be costly to keep in top shape, so condition and service history matter a lot.

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

Accident-free inventory is solid at 84.6% — always verify the vehicle history report.

You should still check the vehicle history report carefully and prioritize a pre-purchase inspection, especially on a luxury SUV with a lot of technology and available equipment. Focus on overall condition, because the GLS combines premium materials, advanced electronics, and multiple powertrain choices that can vary a lot from one listing to the next.

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, 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, and the GLS 450 and GLS 580 route power through a nine-speed automatic transmission to 4MATIC all-wheel drive.
• 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 driver-assistance tech includes 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 infotainment system with a massive touch screen, a central controller, Apple CarPlay, Android Auto, and voice control through “Mercedes” or “Hey Mercedes.” The digital dash and steering-wheel touch pads add capability, but the system has a learning curve.
• Fuel efficiency: The six-cylinder 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 best-value choice if you want the core GLS experience without stepping into the pricier V8 models. You still get the luxury basics, strong standard tech, and the full-size three-row layout, but you avoid the higher running costs that come with the more powerful trims.
• GLS 580: Choose this if you want more power and more comfort features, including heated-and-cooled front seats, massaging front seats, illuminated running boards, soft-close doors, and five-zone climate control. It suits you best if you want a more indulgent version of the GLS and are willing to pay for it.
• Mercedes-AMG GLS 63: This is the performance-focused choice, with the most aggressive styling and the strongest engine in the lineup. It makes sense if you want the most dramatic driving experience and the AMG look, not just the standard luxury-SUV formula.

The GLS also comes with a broad set of standard safety features, while additional driver-assistance tech is available on higher-spec versions.

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

This looks like a moderate, selective buyer’s market.

• Deal availability: 33.2% of listings are priced as good or great deals.
• Inventory: There are 864 listings available.
• Price trend: Prices have softened 9.14% compared with last year.
• Clean inventory: 84.6% of listings are accident-free.

If you find a listing below $46,086, 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 $46,449 sits slightly below last year's $51,123.

That price movement suggests the market has cooled, which can help you buy more confidently now but may also mean slower appreciation if you plan to sell soon. For a future seller, the key takeaway is that resale value will depend heavily on condition, mileage, and trim because the model spans a wide price and equipment range.

The current pricing also shows that buyers are still willing to pay meaningful money for a well-kept GLS, especially given its luxury positioning and three-row utility. If you maintain it carefully and keep service records, you should be in a better position when it’s time to list it again.

Vehicles with strong owner satisfaction ratings, like this model year's 4.7/5, 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.

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 gives you a strong standard safety package, with more advanced driver-assistance features available if you move up or choose the right options. For used shoppers, the main thing to watch is whether the specific listing includes the extra assistance features you want.

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:

• 33.2% of listings are priced as good or great deals.
• Accident-free inventory is solid at 84.6% — always verify the vehicle history report.
• Price trend: Prices have softened 9.14% compared with last year.
• Owners rate it 4.7/5 — a strong satisfaction signal.
• The 2021 GLS stands out for its spacious seating, cargo flexibility, and available performance.

Consider the 2022 if:

• At $46,072, the 2022 costs less than the current year's $46,449 average.
• It simplifies the lineup by leaving only the base six-cylinder GLS 450 4Matic.

The bottom line: If you want the broader 2021 GLS lineup with more trim and powertrain choice, the 2021 is the better fit. If you’re price-sensitive and want the newer model year at a slightly lower average price, the 2022 is worth a look.

How does the 2021 Mercedes-Benz GLS compare to the 2021 BMW X7?

Expert Pros & Cons (per CarGurus review team)

2021 Mercedes-Benz GLS:

• Pros: Multiple powertrain options, Plenty of cargo space, Impressive technology.
• Cons: Cramped third row, Unintuitive technology, Poor fuel economy.

2021 BMW X7:

• Pros: Multiple powertrain options, Great handling, Powerful engine.
• Cons: Advanced safety features are not standard.

Our experts score the 2021 Mercedes-Benz GLS 8.3/10 and the 2021 BMW X7 7.7/10. The GLS leans harder into luxury, cargo space, and technology, while the X7 emphasizes handling and a powerful engine. If you care most about a more spacious, tech-rich full-size SUV, the GLS has the edge; if driving feel matters more, the X7 is the stronger pick.

Read our full side-by-side expert comparison here.

These recommendations are based on CarGurus' proprietary market data from October 21, 2026, CarGurus experts' opinions, and generative AI.