A bus lane or bus-only lane is a lane restricted to buses, often on certain days and times, and generally used to speed up public transport that would be otherwise held up by traffic congestion. The related term busway describes a roadway completely dedicated for use by buses, whilst bus gate describes a short bus lane often used as a short cut for public transport. Bus lanes are a key component of a high-quality bus rapid transit (BRT) network, improving bus travel speeds and reliability by reducing delay caused by other traffic.

In road transport, a lane is part of a roadway that is designated to be used by a single line of vehicles to control and guide drivers and reduce traffic conflicts. Most public roads (highways) have at least two lanes, one for traffic in each direction, separated by lane markings. On multilane roadways and busier two-lane roads, lanes are designated with road surface markings. Major highways often have two multi-lane roadways separated by a median.