1766 (MDCCLXVI) was a common yearstarting on Wednesday of the Gregorian calendarand a common year starting on Sunday of the Julian calendar, the 1766th year of the Common Era (CE) and Anno Domini (AD) designations, the 766th year of the 2ndmillennium, the 66th year of the 18thcentury, and the 7th year of the 1760s decade. As of the start of 1766, the Gregorian calendar was 11 days ahead of the Julian calendar, which remained in localized use until 1923.

• March 18 – Britain repeals the Stamp Act after American protests.

• February 14 – Thomas Malthus, English demographer and economist (died 1834)
• April 6 – Charles Louis de Fourcroy, Chevalier de la Légion d'honneur, French Mathematician and Scholar
• April 22 – Anne Louise Germaine de Stael, French writer (died 1817)
• May 30 – Robert Darwin, Medical doctor and father of Charles Darwin (died 1848)
• July 8 – Dominique Jean Larrey, French surgeon (died 1842)
• August 6 – William Hyde Wollaston, English chemist (died 1828)
• September 6 – John Dalton, English chemist and physicist (died 1844)
• October 23 – Emmanuel, marquis de Grouchy, French marshal (died 1847)
• November 2 – Joseph Radetzky von Radetz, Austrian field marshal (died 1858)
• December 3 – Barbara Fritchie, U.S. patriot in Civil War (died 1862)