Abergavenny (; Welsh: Y Fenni pronounced [ə ˈvɛnɪ], archaically Abergafenni meaning "mouth of the River Gavenny") is a market town and community in Monmouthshire, Wales. Abergavenny is promoted as a Gateway to Wales; it is approximately 6 miles (10 km) from the border with England and is located where the A40 trunk road and the A465 Heads of the Valleys road meet.

Originally the site of a Roman fort, Gobannium, it became a medieval walled town within the Welsh Marches. The town contains the remains of a medieval stone castle built soon after the Norman conquest of Wales.

Abergavenny is situated at the confluence of the River Usk and a tributary stream, the Gavenny. It is almost entirely surrounded by mountains and hills: the Blorenge (559 m, 1,834 ft), the Sugar Loaf (596 m, 1,955 ft), Ysgyryd Fawr (Great Skirrid), Ysgyryd Fach (Little Skirrid), Deri, Rholben and Mynydd Llanwenarth, known locally as "Llanwenarth Breast". Abergavenny provides access to the nearby Black Mountains and the Brecon Beacons National Park. The Marches Way and Beacons Way pass through Abergavenny whilst the Offa's Dyke Path passes through Pandy five miles to the north and the Usk Valley Walk passes through nearby Llanfoist.

In the UK 2011 census, the six relevant wards (Lansdown, Grofield, Castle, Croesonen, Cantref and Priory) collectively listed Abergavenny's population as 12,515. The town hosted the 2016 National Eisteddfod of Wales.