Johann Fischer may refer to:

• Johann Georg Fischer (painter) (1580–1643), German historical painter
• Johann Fischer (theologian) (1636-1705), German Lutheran theologian
• Johann Fischer (composer) (1646–1716), German violinist, pianist, and composer of the Baroque era
• Johann Caspar Ferdinand Fischer (1656–1746), German Baroque composer
• Johann Christian Fischer (1733–1800), German composer and oboist
• Johann Ignaz Ludwig Fischer (c. 1745–1825), German opera singer
• Johann Georg Fischer (1816–1897), German poet and playwright

• Johann Bernhard Fischer (1685–1772), German doctor, medical adviser to Empress Anna
• Johann Fischer von Waldheim (1771–1853), German anatomist, entomologist, and paleontologist
• Johann Conrad Fischer (1773–1854), Swiss metallurgist
• Johann Nepomuk Fischer (1777–1847), Austrian ophthalmologist
• Johann Baptist Fischer (1803–1832), German naturalist, zoologist, and botanist
• Johann Gustav Fischer (1819–1889), German herpetologist

• Johann Bernhard Fischer von Erlach (1656–1723), Austrian architect, sculptor, and architectural historian
• Johann Michael Fischer (1692–1766), German architect in the late Baroque period
• Johann Erhard Fischer (1817–1884), German Lutheran pastor

• John Fischer (disambiguation)
• John Fisher (disambiguation)
• Johannes Fischer (1887–?), German physicist