- May 1 Antonius van Alphen, apostle vicar of De Bosch, dies at 82
- May 13 Christian Gottfried Körner, German lawyer, dies at 74
- May 26 Georg Hermes, German philosopher and theologist (Hermenianen), dies
- May 26 Ciro Menotti, Italian patriot (b. 1798)
- May 27 Jedediah Smith, American explorer (b. 1799)
- May 31 Samuel Bentham, British mechanical engineer (b. 1757)