The men's 100 metre backstroke event at the 1956 Olympic Games took place between 4 and 6 December.
Because an Olympic size swimming pool is 50 metres long, this race consisted of two lengths of the pool.
Four heats were held; the swimmers with the sixteen fastest times advanced to the Semifinals.
Two heats were held; the swimmers with the eight fastest times advanced to the Finals.
Key: WR = World record