František Xaver Brixi (January 2, 1732 – October 14, 1771) was a Czech classical composer of the 18th century. His first name is sometimes given, by reference works, in its Germanic form, Franz.
Brixi was born in Prague, the son of composer Šimon Brixi. He received his musical education at the Piarist Gymnasium in Kosmonosy. His teachers included Václav Kalous, a significant composer himself.

In 1749 Brixi left Kosmonosy and returned to Prague, where he worked as an organist at several churches. In 1759 he was appointed Kapellmeister of St Vitus Cathedral, thus attaining, at the age of only 27, the highest musical position in the city; this office he held till his early death. He wrote some 290 church works (of the most varied type), cantatas and oratorios, chamber compositions, and orchestral compositions. His organ concertos, which have been recorded several times each, are his best-known pieces today.
Brixi's style is distinguished from that of his contemporaries by its fresh melodic writing, vivacious rhythm and lively bass lines, and from that of his predecessors by its simple yet effective instrumentation. During his lifetime his music was widely disseminated in Bohemia and Moravia.