Bethmann is a German surname. Notable people with the surname include:
The Bethmann family in Germany, originally from Goslar, achieved greatest prominence in Frankfurt am Main; the Bethmann-Hollweg sideline produced a German chancellor.
Konrad Bethmann (1625–1701), Münzwardein and Münzmeister in Nassau and other German places
Johann Philipp Bethmann (1715–1793), grandson of Konrad Bethmann, merchant and banker in Frankfurt am Main
Johann Jakob Bethmann (1717–1792), grandson of Konrad Bethmann, merchant, shipowner and consul in Bordeaux
Simon Moritz Bethmann (1721–1782), grandson of Konrad Bethmann, merchant and banker in Frankfurt am Main
Simon Moritz von Bethmann (1768–1826), son of Johann Philipp Bethmann (1715–1793), banker and statesman in Frankfurt am Main
Moritz von Bethmann (1811–1877), son of Simon Moritz von Bethmann, banker and merchant in Frankfurt am Main
Ludwig Simon Moritz Freiherr von Bethmann (1844–1902), son of Moritz von Bethmann, banker in Frankfurt am Main
Moritz Henning August Freiherr von Bethmann (1887-1966), son of Ludwig Simon Moritz Freiherr von Bethmann, banker in Frankfurt am Main
Johann Philipp von Bethmann (1924–2007), son of Moritz Henning August Freiherr von Bethmann, banker and book author in Frankfurt am Main
August von Bethmann-Hollweg (1795–1877), grandson of Johann Philipp Bethmann (1715–1793), Prussian jurist and politician
Theobald von Bethmann Hollweg (1856–1921), grandson of August von Bethmann-Hollweg, German politician
Alexandre de Bethmann (1805-1871), mayor of Bordeaux from 1867 to 1870, great-grandson of Johann Jakob Bethmann
Pierre de Bethmann (1961-), French jazz pianist, 5th-generation descendant of Alexandre de Bethmann
Heinrich Eduard Bethmann (1774–1857), German actor and theater director
Ludwig Konrad Bethmann (1812–1867), German historian
Erich Waldemar Bethmann (1904-1993), Author and religious scholar
Sabine Bethmann (b. 25 October 1931), former German movie actress
Andreas Bethmann (19??-), German film director