The Scion xB is a vehicle made by Toyota for the United States market and sold under their youth-oriented Scion brand. It is a box-shaped, 5-door compact station wagon.

The first-generation xB was a lightly-modified and rebadged version of the Japanese-market subcompact Toyota bB. It was a small station wagon based on the Toyota Echo/Yaris platform. The xB was one of two models in the lineup of Toyota's US-exclusive Scion division present at the brand's 2004 launch, the other being the xA, based on the Toyota ist.

First generation xB vs. first generation bB

Only the first generation models for both the xB and bB are related. Second generation models are based upon different platforms.

To create the first generation xB, the bB was modified from right- to left-hand drive, the front passenger area was also changed significantly with the bB's front bench seat replaced with bucket seats and the column-mounted shifter changed to a floor-mounted shifter.

The available drivetrains also differed. The bB was available with either the 1.3 L I4 2NZ-FE engine or the 1.5 L 1NZ-FE, mated exclusively to a 4-speed automatic transmission with available all wheel drive. The xB was only available with the 1NZ-FE that produced 108hp (81kW) and 105lb·ft (142N·m) in US spec, but offered both a 4-speed automatic or a 5-speed manual transmission. All-wheel drive was not offered on the xB.

The Toyota bB was not equipped with a spare tire. On the Scion xB, a compact spare tire was stored under the left side of a raised rear cargo floor. Since the spare tire raised the cargo floor by several inches, a storage bin was added to the right of the spare tire to reclaim some of the lost storage space. A jack was stored under the driver's seat of the xB.