De Sitter (disambiguation)

Willem de Sitter (1872–1934) was a Dutch mathematician, physicist and astronomer.

De Sitter may also refer to:
 * De Sitter (crater), a lunar crater
 * 1686 De Sitter, an asteroid

People with the surname

 * Ulbo de Sitter (1902–1980), Dutch geologist
 * Ulbo de Sitter (sociologist) (1930–2010), Dutch sociologist whose work has been further developed by Jan in 't Veld