HomeNewsKBB Expert Reviews

Sibling Rivalry: 2021 Mercedes-Benz GLA 250 4MATIC versus 2021 Mercedes-Benz GLB 250 4MATIC

Which of these Mercedes-Benz cute-ute siblings is the best choice if you are shopping for a small and luxurious SUV?


The appeal of a small and luxurious SUV is not a new idea in automotive showrooms. For example, BMW has its X1 sub-compact SUV and its X2 sibling that sports a sleeker offline at the sacrifice of rear passenger and cargo space. Mercedes-Benz offers a similar sibling rivalry in the form of its 5-passenger sub-compact GLA coupé/SUV and its more upright and roomier GLB counterpart that can seat up to 7 passengers.

The 2021 GLA-Class is the smallest and most affordable new Mercedes-Benz SUV you can buy, and this 2nd-generation GLA is much roomier inside. The automaker sees the GLA as more of a sporty lifestyle-oriented SUV than the more traditionally shaped GLB.

The 2021 Mercedes-Benz GLB-Class carves out its particular niche between the automaker's GLA-Class and compact GLC-Class SUVs—if anything, it's closer in size to the GLC. The GLB's relatively long wheelbase results in a vehicle that's roomier inside than its modest dimensions might suggest, which is why it can offer three rows of seats, albeit the 3rd-row is best-suited to kids.

The GLA-Class and GLB-Class share a front-wheel-drive-based platform along with Mercedes-Benz’s A-Class Sedan and Hatch and CLA 4-door Coupe.

So which one to choose? Read on to find out which of these Mercedes-Benz sub-compact SUV siblings is just right for you.



While the Mercedes-AMG versions are marketed at higher price and performance levels, the base 2021 GLA 250 4MATIC is the affordable gateway to the expanding world of Mercedes-Benz SUVs. With one engine/transmission combo and all-wheel-drive standard, the GLA 250 4MATIC’s Manufacturer’s Suggested Retail Price in Canadian dollars starts at $42,400.

Sharing the same powertrain, the 2021 GLB 250 4MATIC's base price starts at $46,500. For that price, the GLB matches the GLA's 2-row/5-passenger setup. But if you want the GLB's extra pair of 3rd-row seats, Mercedes-Benz wants another $1,300 in exchange.

As with most Mercedes-Benz models, the base prices are just the start. Both the GLA and GLB offer many optional packages, and both come with a 4-year/80,000-kilometre comprehensive factory warranty.

Winner: 2021 Mercedes-Benz GLA 250 4MATIC



It’s clear that Mercedes-Benz spent a lot of time refining the interior of both the GLA and GLB. Both are luxurious and handsome places, with modern high-tech touchscreens and materials that are of high quality. 

The GLA's front seat accommodates large drivers very well, offering more front headroom and rear legroom than its taller sibling. Plus, there's enough room for an adult to sit reasonably comfortably behind a driver of the same height in the back seats.

Where the taller, longer and boxier GLB excels is in interior cargo space. Its reclining 2nd-row slides back and forth to create either extra legroom or greater cargo volume. Behind the front seats, there are 1,755 litres of cargo space—325 more than in the GLA. When all seven seats are in use, the GLB offers up to 560 litres of cargo room compared to only 435 in the smaller GLA.

Note that although the GLB’s two individual retractable 3rd-row seats are available, they’re small. Mercedes-Benz acknowledges this, stating that they’re suitable only for people 5-foot 6-inches or shorter.

Winner: 2021 Mercedes-Benz GLB 250 4MATIC


Performance & Fuel Economy

Sharing a platform and a powertrain, it’s no surprise there’s not a lot to differ between the sleeker GLA 250 4MATIC and the more utilitarian GLB 250 4MATIC when it comes to how they perform and consume fuel.

In both baby ‘Benz SUVs, a turbocharged 2.0-litre 4-cylinder engine puts out 221 horsepower and 258 pound-feet of torque. That power gets sent to all four wheels via an 8-speed dual-clutch automatic transmission with shift paddles behind the GLA/GLB’s respective steering wheels.

Because it weighs 180 kilograms less than the GLB’s 1,765-kilogram curb weight, the GLA scores a more efficient 8.7 litres per 100 kilometres combined city and highway estimate, beating the GLB’s 9.2 rating. And according to the automaker’s numbers, the GLA is quicker accelerating from zero to 100 kilometres per hour, taking only 6.7 seconds versus the GLB’s 6.9 time.

Winner: 2021 Mercedes-Benz GLA 250 4MATIC


Ride and Handling

Drive a 2021 Mercedes-Benz GLA 250 4MATIC, and you’ll immediately appreciate the solidity of its structure. It feels solid and robust, and the tidy overall footprint makes the GLA an ideal runabout in crowded Canadian cities. The suspension is tuned for sportiness. It’s firm, not harsh, but perhaps not quite up to the dignified suppleness of a Mercedes-Benz E-Class mid-size luxury sedan. Around town, the automatic transmission shifts smoothly and when expected, aided by shift paddles that let you downshift for a bit of engine braking on downhill stretches.

Similarly, the 2021 GLB 250 4MATIC is quiet, easy to see out of, and a delight to drive. It has ample power, natural-effort steering, and strong brakes. Superb overall comfort, supple ride quality, selectable driving modes, and a contemporary interior make the GLB refined enough for everyday use and long cross-country drives. Respectable ground clearance and short overhangs also help on cottage trails or snowy roads.

Winner: 2021 Mercedes-Benz GLB 250 4MATIC


Overall Winner: Tie

Unless you’re a Mercedes-Benz Canada dealer, nobody likes a tie. But after adding up the wins in our four categories, we found the differences between this pair of Mercedes-Benz sub-compact SUVs too close to call an outright winner.

Mercedes-Benz describes its GLA 250 4MATIC as “compact and sleek.” And that description manifests itself not only in the small ‘Benz’s sleek exterior styling but also by offering the best fuel economy and quicker acceleration times when compared to its sibling.

However, the GLB 250 4MATIC lives up to its description as “family-friendly” by offering more cargo space, the ability to carry two more (albeit smaller) humans and a more appropriate ride and handling package to deal with adverse Canadian roads.


2021 Mercedes-Benz GLA 250 4MATIC

2021 Mercedes-Benz GLB 250 4MATIC


2.0-litre Turbocharged I4

2.0-litre Turbocharged I4


221 @ 5,500 rpm

221 @ 5,500 rpm


258 lb-ft @ 1,800-4,000 rpm

258 lb-ft @ 1,800-4,000 rpm


8-speed automatic

8-speed automatic

Fuel Economy

8.7 L/100 km (9.8 city, 7.2 hwy)

9.2 L/100 km (10.3 city, 7.8 hwy)


4 years/80,000 km

4 years/80,000 km

Max Seating Capacity



Curb Weight

1,585 kg

1,765 kg


2,729 mm

2,829 mm

Overall Length

4,410 mm

4,634 mm


2,020 mm

2,020 mm


1,611 mm

1,658 mm

Headroom, Front

1,037 mm

1,035 mm

Headroom, Rear

969 mm

982 mm

Legroom, Front

1,045 mm

1,045 mm

Legroom, Rear

976 mm

937 mm

Shoulder Room, Front

1,419 mm

1,419 mm

Shoulder Room, Rear

1,393 mm

1,396 mm

Cargo Volume, Behind 1st-row Seats

1,430 L

1,755 L


Cargo Volume, Behind 2nd-row Seats

435 L

560 L


Find the Price of your New or Used Car


Find Your Next Car