Wentzel and Wentzell are surnames, and may refer to:

Wentzel

• Emil Wentzel (c. 1817–1892), timber merchant and politician in South Australia

• Gregor Wentzel (1898–1978), German physicist

• Stan Wentzel (1917–1991), Major League Baseball player

• Sune Wentzel (born 1971), Norwegian frisbee player

• Uta Wentzel (born 1979), German politician

• Volkmar Wentzel (1915–2006), American photographer

Wentzel may also refer to:

• Wentzel–Kramers–Brillouin approximation

Wentzell

• Alexander D. Wentzell (born 1937), Russian-American mathematician

• Fritz Wentzell (1899–1948), highly decorated German military leader during World War II

Wentzell may also refer to:

• Freidlin–Wentzell theorem, a statistics tool relating to Brownian motion