Category:Northern Irish registered buses in the United Kingdom

English: Buses pictured in the United Kingdom pictured wearing Northern Irish registration plates. For completeness, images in this category should also be categorised by year in one of the appropriate equivalent GB-format branches of the parent category, Category:Buses in the United Kingdom by year of registration

In the United Kingdom registration plate system, numbers issued in Northern Ireland have always had different format to those issued in Great Britain. After earlier shorter systems, since 1966 the Northern Irish format has been "AXX 1234", where "XX" denotes the issuing county, the "A" is a serial letter, and the "1234" are serial numbers. The county code always includes either a "Z" or an "I".

As well as being issued to vehicles that stay in Northern Ireland (see Category:Northern Irish registered buses in Northern Ireland), it is not uncommon to see a Northern Irish registered bus in Great Britain for various reasons (see Category:Northern Irish registered buses in Great Britain), not least because it is not possible to tell the age of the vehicle from the plate in the Northern Irish system.

In an analogy to the Q plate in the GB format which is reserved for vehicles with indeterminate age, such vehicles in Northern Ireland are given the code QNI.