Used 2021 Mercedes-Benz GLS for Sale nearPittsburgh, PA

How much does the 2021 Mercedes-Benz GLS cost?

Prices have softened 9.81% compared to this time last year, making it a favorable time to shop this model year.

There are 772 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 GLS is built around a full-size, three-row luxury-SUV mission, with spacious seating, a comfort-first character, and plenty of cargo room for larger loads. It also brings multiple powertrain choices and a high-end presentation that help it stand out in the segment.

The main trade-offs are a cramped third row and technology that can feel unintuitive, along with poor fuel economy.

Good and great deals account for 34.8% of listings, so you have some 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 refined, comfort-focused luxury SUV, and its overall package emphasizes upscale materials, strong performance, and everyday usefulness. The expert notes also point to a composed ride and a vehicle that feels easy to maneuver for its size.

Its performance content highlights a mild-hybrid setup that supports the powertrains, and the system is described as helping add extra power when needed while also aiding turbo response. That kind of engineering can support smooth operation over time when the vehicle is maintained properly.

If you buy used, the biggest long-term ownership risk is that a complex luxury SUV can be costly to keep in top shape, especially if prior maintenance was inconsistent.

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

Accident-free inventory is solid at 83.5% — always verify the vehicle history report.

You should still check the report carefully, because a clean listing percentage does not replace a proper history review. Prioritize a pre-purchase inspection that focuses on electronics, suspension behavior, and interior wear, since this is a technology-heavy luxury SUV. You should also pay close attention to how the third row, cargo area, and cabin controls have held up in real 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 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, a chrome slotted grille, and a performance-inspired interior. The GLS 450 is the best-value trim if you want the core luxury and tech without moving up for extra power.
• 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.
• 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 touch screen, a central controller, Apple CarPlay, Android Auto, and voice control. The system relies on a USB-C cable for phone connection, and the interface can take some learning.
• 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 core luxury features, the MBUX infotainment system, and the standard safety suite, so it covers the essentials well.
• GLS 580: This trim adds V8 power plus comfort upgrades like heated-and-cooled front seats, massaging front seats, illuminated running boards, soft-close doors, and five-zone climate control. It is the right choice if you want more performance and a richer cabin without going all the way to the AMG model.
• Mercedes-AMG GLS 63: This is the performance-focused version, with the most powerful engine, more aggressive styling, and a sportier cabin. It makes sense if you want the most dramatic driving character and are willing to pay for it.

The GLS comes standard with a full array of driver-assistance features, while additional safety tech is available on higher-spec or optioned versions.

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

This is a moderate market for selective buyers, so you can shop carefully and still find opportunities.

• Deal availability: 34.8% of listings are priced as good or great deals.
• Inventory: There are 772 listings available.
• Price trend: Prices have softened 9.81% compared with last year.
• Clean inventory: 83.5% of listings are accident-free.

If you find a listing below $47,873, 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 $47,956 sits slightly below last year's $53,175.

That decline suggests the market has become more favorable for buyers, but it also means a future seller may need to price competitively to stand out. If you buy at today's average or below, you may have less downside risk than someone who bought when prices were higher. The GLS's luxury positioning and broad appeal can still support demand, especially if the vehicle is well kept and properly equipped.

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, 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 upgrades include lane-keep assist, lane-change assist, adaptive cruise control, a following-distance indicator, and stop-and-go cruise control.

The safety package is strong, but some of the more advanced driver-assistance features are not standard, so you may need to shop carefully if you want the fullest suite.

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:

• 34.8% of listings are priced as good or great deals.
• Accident-free inventory is solid at 83.5% — always verify the vehicle history report.
• Price trend: Prices have softened 9.81% compared with last year.
• Owners rate it 4.67/5 — a strong satisfaction signal.
• The 2021 GLS delivers three-row luxury, multiple powertrain choices, and a comfort-first cabin.

Consider the 2022 if:

• At $47,864, the 2022 costs less than the current year's $47,956 average.
• Mercedes narrowed the lineup to the base six-cylinder GLS 450.

The bottom line: If you want the broadest mix of trims, powertrains, and luxury content, the 2021 is the stronger all-around pick. If your priority is simply getting into a GLS at the lowest comparable price, the 2022 can make sense as a more price-sensitive alternative.

These recommendations are based on CarGurus' proprietary market data from September 11, 2026, CarGurus experts' opinions, and generative AI.