St Fagans National Museum of History
| Sain Ffagan: Amgueddfa Werin Cymru | |
| The administration offices in the background | |
| Former name | St Fagans National History Museum | 
|---|---|
| Established | 1948 | 
| Location | St Fagans, Cardiff, Wales | 
| Coordinates | 51°29′13″N 3°16′21″W / 51.4869°N 3.2725°W | 
| Visitors | 610,155 (2010) * Ranked 21st in the UK | 
| Website | museum | 
St Fagans National Museum of History (/ˈfæɡənz/ FAG-ənz; Welsh: Sain Ffagan: Amgueddfa Werin Cymru), commonly referred to as St Fagans after the village where it is located, is an open-air museum in St Fagans, Cardiff, Wales, chronicling the historical lifestyle, culture, and architecture of the Welsh people. The museum is part of the wider network of Amgueddfa Cymru – Museum Wales.
It consists of more than forty re-erected buildings from various locations in Wales, and is set in the grounds of St Fagans Castle, a Grade I listed Elizabethan manor house. In 2011 Which? magazine named the museum the United Kingdom's favourite visitor attraction.
A six-year, £30-million revamp was completed in 2018 and the museum was named the Art Fund Museum of the Year in 2019.