Jakub Šimon Jan Ryba (surname also Poisson, Peace, Ryballandini, Rybaville; 26 October 1765 – 8 April 1815) was a Czech teacher and composer of classical music. His most famous work is Czech Christmas Mass "Hey, Master!" (Česká mše vánoční "Hej mistře!").
Ryba was born in Přeštice near Plzeň. His father was a schoolteacher, which was a very poorly paid occupation at the time. In 1780 Ryba went to Prague, where he studied at the Piarist gymnasium. His teacher Cassianus Hanel taught him music. Ryba was a very good student and he soon started to compose. He dreamt of being a famous composer. In 1784 his father ordered him to work as a teacher in Nepomuk. Ryba reluctantly obeyed, but he was soon fired. After wandering for a few months, he received a message that his mother had died. After a long illness, he moved to Mníšek pod Brdy. Being popular among local inhabitants for performing music, he was quite happy there, but after some hesitation he accepted a schoolteacher position in Rožmitál pod Třemšínem.