Bangor Mountain is a the scarp face of a hill below which the city of Bangor in Wales, UK sits.

Though not a mountain in the true sense of the word it is so called because of the way it rears up behind Bangor and appears mountainous, especially from the Glan Adda, High Street and Hirael areas of the city.

Bangor Mountain is much less precipitous on its southern side. Along a substantial part of the crest of the mountain is Bangor Golf Club—more properly St Deiniol's Golf Club. Because of the shape of the mountain, the golf course is linear and crosses some lanes and minor roads.

There are several rocky outcrops at high points on the mountain providing panoramic views of the city centre, the Menai Strait and over to the east of Anglesey, including the town of Beaumaris. This is probably the best location from which to see the buildings of the University of Wales, Bangor and the cathedral—as shown in the image below.

Along the side of the high street, the scarp slope is nearly vertical and clothed with trees. The slope is so severe and the mountain so close, that much of the High Street does not receive direct sunlight between November and March.

Bangor Mountain has a diverse ecology with a variety of mixed woods , open grassland and extensive areas of gorse although biodiversity appears to be significantly reduced within the confines of the golf course. Around the rocky outcrops and alongside some of the many paths that weave their way around the mountain are large deposits of litter (paper, cans and plastic bags).

The extensive groves of gorse are often set alight by arsonists in dry summers producing a blaze that can be seen for many miles around. Whilst this may benefit the gorse and the ecosystem based around gorse, the fires often spread into other areas of established woods where considerable damage is caused.

Bangor Mountain provides the main southern watershed for the River Adda , the principal river flowing through Bangor. However, as the river has now been culverted throughout its whole length in the built up area of the city, it is little known to the city's population.

Part of Bangor Mountain was unlawfully removed in 2004 to provide car parking for a new discount supermarket. As a result the footpath in this area now approaches very close to a precipitous edge protected by two-metre high railings topped with saw tooth edging.