Colby is a surname. Notable people with the surname include:
Anita Colby (1914–1972), actressAnthony Colby (1792–1873), Governor of New HampshireBainbridge Colby (1869–1950)Barbara Colby (1940–1975), actressC.B. Colby (1904-1977) American authorCharles Carroll Colby (1827–1907), Canadian politicianDanielle Colby (born 1975), burlesque dancer, fashion designer and American reality television personalityEverett Colby, New Jersey state SenatorFlick Colby (1946-2011), dancer in the British troupe Pan's PeopleFrank Moore Colby (1865–1925), educator and writerGerard Colby, authorJamie Colby, TV presenterJohn Colby (1787–1813), preacherJohn Colby (musician), American musicianThomas Frederick Colby (1784–1852), geographerWilliam Colby (1920–1996), Director of the CIAWilliam Edward Colby (1865–1974), first Secretary of the Sierra Club