Joost is a male Dutch first name. It derives from the name Jodocus, which can ultimately be traced back to St. Judoc, a Breton saint of the 7th century: Jodocus → Josse → Joos → Joost (the addition of an end-t is a peculiarity of the Dutch language, especially some local dialects).

Sometimes the (originally Ancient Roman) name Justus was used to represent Joost.^[1] This may have led to confusion between Justus and Jodocus as the origin of Joost. In Dutch proper it is pronounced [ˈjoːst]. In Afrikaans it is pronounced [ˈjust].

• Eddie Joost (1916–2011), American baseball player
• Gesche Joost (born 1974), German design researcher
• Oskar Joost (1898–1941), German musician
• Risto Joost (born 1980), Estonian conductor and operatic countertenor