Thomas Henry Wyatt (9 May 1807 – 5 August 1880) was an Irish British architect. He had a prolific and distinguished career, being elected President of the Royal Institute of British Architects 1870–73 and awarded their Royal Gold Medal for Architecture in 1873. His reputation during his lifetime was largely as a safe establishment figure and critical assessment has been less favourable more recently, particularly in comparison with his younger brother, the better known Matthew Digby Wyatt.
Wyatt was born at Lough-Glin House, County Roscommon. His father was Matthew Wyatt (1773–1831) a barrister and police magistrate for Roscommon and Lambeth. Wyatt is presumed to have moved to Lambeth with his father in 1825 and then initially embarked on a career as a merchant sailing to the Mediterranean, particularly Malta.
He married his first cousin Arabella Montagu Wyatt (1807–1875). She was the second daughter of his uncle Arthur who was agent to the Duke of Beaufort. This consolidated his practice in Wales.
Wyatt worked in many styles ranging from the Italianate of Wilton through to the Gothic of many of his churches.
His practice was extensive with a large amount of work in Wiltshire largely as a result of his official position and the patronage of the Herbert family and in Monmouthshire through the Beaufort connection
Llantarnam Abbey was Wyatt's first (?) Monmouthshire house (1834-5) for Reginald Blewitt. Large mansion in the Elizabethan style, built on a dissolution site. Once again an abbey, in possession of the Sisters' of St. Joseph.