Bus spotting is a pastime in which one seeks to see all buses in a particular fleet or those produced by a particular manufacturer. A person who engages in these activities is known as a bus spotter or a bus enthusiast. Within the bus industry bus spotters are known as moquettes, from the material used to make the seat coverings. As with train or aircraft spotters, bus spotters spend much time outdoors with notepads, monitoring bus routes. Some bus enthusiasts are only interested in vintage vehicles, and some prefer trolleybusses.

Bus spotters are relatively unconcerned by timetables or network quality but they may be interested in new liveries, especially ad-hoc schemes to advertise particular products or events. Some may be so keen that they might track a vehicle through its life, knowing for example which fleet numbers it has carried with different owners and when mechanical parts or interior fittings were renewed. Bus spotting has never had the wide following achieved by train spotting in the UK, but has become popular in Hong Kong and many bus societies have been formed there.

Bus spotters usually like to keep abreast of the news about buses. They may also like to take photographs of buses and ride on them. Since bus spotting involves urban mass transit, it often goes hand in hand with metrophily. In New York, the two are often combined into "transit fan", a person who studies both bus and rail rapid transit, with the same diligence.

The term bus enthusiast may have a wider meaning than just spotting buses, meaning someone with an interest not just in vehicles, but also in the operation of bus companies and their fleets in general.

Bus spotters also like to have 'fan charters' by chartering a bus of choice and get photos of it in different parts of the city or town they are in.

Bus spotters are usually found at major bus Terminal, Bus depots and anything related to buses.

The bus spotters attire includes usually being a man, a heart dedicated to mass transit, a camera bag and camera or camcorder, and a notepad. They sometimes get mistaken for being Terrorists resulting in a lot of criticism from transit staff and riders alike.