An anti-lock braking system (ABS) (translated from German, Antiblockiersystem) is a system on motor vehicles which prevents the wheels from locking while braking. An anti-locking braking system allows the driver to maintain steering control under heavy braking by preventing a skid and allowing the wheel to continue to forward roll and create lateral control, as directed by driver steering inputs. Most commonly, braking distances are shortened (again, by allowing the driver to press the brake fully without skidding or loss of control). Disadvantages of the system include increased braking distances under rather rare circumstances and the creation of a "false sense of security" among drivers who do not understand the operation and limitations of ABS.

Since it came into widespread use in production cars (with "version 2" in 1978), ABS has made considerable progress. Recent versions not only handle the ABS function itself (i.e. preventing wheel locking) but also traction control, brake assist, and electronic stability control, amongst others. Not only that, but its version 8.0 system now weighs less than 1.5 kilograms, compared with the 6.3 kg version 2.0 in 1978.