Bangor (English: ; Welsh: [ˈbaŋɡɔr] (listen)) is a cathedral city and community in Gwynedd, North Wales. It is the oldest city in Wales. Historically part of Caernarfonshire, it had a population of 18,322 at the 2019 UK Office for National Statistics. The city is best known for local landmarks such as Menai Suspension Bridge connecting the city and Isle of Anglesey, Bangor Cathedral, Bangor University and Garth Pier.

The origins of the city date back to the founding of a monastic establishment on the site of Bangor Cathedral by the Celtic saint Deiniol in the early 6th century AD. 'Bangor' itself is an old Welsh word for a wattled enclosure, such as the one that originally surrounded the cathedral site. The present cathedral is a somewhat more recent building and has been extensively modified throughout the centuries. While the building itself is not the oldest, and certainly not the biggest, the bishopric of Bangor is one of the oldest in the UK.