BMW X3 vs Mercedes-Benz GLB-Class

The short version

The BMW X3 is more fuel-efficient: 29 vs 28 MPG combined in its best version.

That works out to about $100 a year less in fuel for the BMW X3 (EPA estimate, 15,000 miles).

The BMW X3 is the bigger car, about 5 inches longer.

Across all model years since 2005, the Mercedes-Benz GLB-Class has had fewer recall campaigns (0 vs 62).

The two cars

The 2026 BMW X3 is a small SUV offered with 2 engines (2.0L 4-cyl turbo and 3.0L 6-cyl turbo), including a hybrid version and all-wheel drive. It measures about 187 inches long and 76 inches wide on a 113-inch wheelbase, with a curb weight of roughly 4,176 lb (30 Xdrive 4dr SUV).

The 2026 Mercedes-Benz GLB-Class is a special purpose vehicle offered with a 2.0L 4-cyl turbo engine, including a hybrid version and front-wheel drive and all-wheel drive. It measures about 182 inches long and 72 inches wide on a 111-inch wheelbase, with a curb weight of roughly 3,759 lb (250 4matic 4dr SUV).

Buying used? The 2023 X3 and the 2024 GLB-Class have the fewest problems in our data; avoid the 2020 X3.