Hornig is a surname. Notable people with the surname include:
Donald Hornig (1920–2013), American chemist, explosives expert, teacher and presidential science advisor
Ernst Hornig (1894-1976), German Bishop of the Evangelical Church of Silesia
Heinz Hornig (born 1937), former German football player
Irina Hornig, skydiver who competed for the SC Dynamo Hoppegarten/ Sportvereinigung (SV) Dynamo
Joan Hornig, American jewelry designer
Károly Hornig (1840–1917), Austrian-Hungarian Cardinal of the Roman Catholic Church
Mady Hornig, MD (born 1957), psychiatrist, associate professor of epidemiology at Columbia University's Mailman School of Public Health
Manuel Hornig (born 1982), German football player
