客车是在设计和技术特性上用于载运乘客及其随身行李的载客车辆，包括驾驶员座位在内，座位数应超过九座，属于商用车辆的范畴。客车的形式多种多样，有单层或双层，有单节式也有牵引挂车的铰接客车。中国大陆及香港的术语标准把在城市间运行的载客车辆称为长途客车，在城市里运行的载客车辆称成为公共汽车、城市客车或巴士。

通常客车以柴油、汽油或者液化石油气、压缩天然气做燃料的内燃机驱动，近年来有不少客车使用燃料电池、蓄电池或电容器供电，使用电动机驱动（与无轨电车和电瓶车不同，这类客车一般称作电动客车）。

A coach (also motor coach, often simply referred to as a bus) is a type of vehicle used for conveying passengers on excursions and on longer-distance intercity bus service between cities—or even between countries. Unlike transit buses designed for shorter journeys, coaches often have a luggage hold that is separate from the passenger cabin and are normally equipped with facilities required for longer trips, including comfortable seats and sometimes a toilet.