Henry Thomas Smart (26 October 1813 – 6 July 1879) was an English organist and composer.

Though highly rated as a composer by his English contemporaries, Smart is now largely forgotten, save for his hymn tune "Regent Square", which retains considerable popularity, and which is commonly performed with the words "Christ is Made the Sure Foundation", "Light's Abode, Celestial Salem", or "Angels from the Realms of Glory".

His many compositions for the organ (some of which have been occasionally revived in recent years) were described as "effective and melodious, if not strikingly original" in the Encyclopædia Britannica Eleventh Edition (1911), which also praised his part songs.

The oratorio Jacob was created for Glasgow in 1873; and his comic opera Bertha or The Gnome of Hartzburg was produced with some success at the Haymarket in June 1855.

He was horrified when, in 1935, The Methodist Hymnal instead set the lyrics to John Hughes' "Cwm Rhondda".