Jean-Xavier Lefèvre (Lausanne Cressis, 6 March 1763 – Paris Neuilly, 9 November 1829) was a Swiss-born French clarinettist and composer.
In 1778, at the age of 15, Lefèvre became a member of the French Guards band.
When the National Guard was formed in the year of the Revolution he played in this and from 1790 was its deputy conductor.
He had many famous pupils at the Paris Conservatoire who included Janssen 1795/6, Péchignier 1797, Crusell 1803, Buteux 1814 to 1819, Crépin 1816 to 1821, Adolphe Hugot 1817 to 1822 and Pierre Hugot 1820 to 1824.
During Lefèvre's term of office the contest piece had always to be the composition of the professor and Sainsbury mentions that in 1799 Lefèvre set his Concerto no.5.