Jonathan Gwyn Adams Bristol, England, July 1961) is a Welsh architect particularly known for his landmark buildings in Cardiff.

Percy Thomas Partnership was the trading name of the award-winning British architectural practice established some time between 1965 and 1973 as the successor to a series of earlier partnerships originally set up by Percy Thomas (1883–1969) in Cardiff, Wales in 1911/12. Percy Thomas and the Percy Thomas Partnership put their name to a number of landmark buildings in the United Kingdom including the Wales Millennium Centre, Cardiff. It opened offices overseas and completed a number of prestigious buildings in Hong Kong.