Wirth is a German surname which may refer to any of the following individuals:
- Ann Fisher-Wirth (1947–Present), American poet and university professor
- Christian Wirth (1885–1944), notorious member of the Nazi Schutzstaffel (SS) involved in the Action T4 program and Operation Reinhard
- Christian Wirth (a.k.a. RaD Man), computer art historian and founder of ACiD
- George Wirth (1947-Present), a singer-songwriter from New Jersey.
- James Wirth (listed as Peter Wirth)
- John Wirth (1936–2002), American historian and university professor
- Karl Joseph Wirth (1879–1956), Chancellor and Finance Minister of Germany
- Louis Wirth (1897–1952), American sociologist of German origin and member of the Chicago School of sociology
- Max Wirth (1822–1900), German journalist and economist
- Niklaus Wirth (1934–Present), Swiss computer scientist, designer of several programming languages
- Nick Wirth (1966-Present), British automotive engineer
- Oswald Wirth (1860–1943), Swiss Tarot writer and occultist
- Friar (James) Peter Wirth (1830–1871), founder of the congregation of the Franciscan brothers of the Holy Cross (FFSC)
- Theodore Wirth (1863–1949), Swiss born, horticulturalist, architect of Minneapolis park system
- Tim Wirth (1939–Present), former United States Senator and leader of the United Nations Foundation
- Wilhelm Wirth (1876–1952), German psychologist
- Donald Robert Wirth (1957–Present), noted engineer and automation specialist
- Dr Hugh Wirth, President of the Victoria RSPCA and was named Victorian of the Year in 1997.
Wirths
- Eduard Wirths, Nazi SS chief physician at Auschwitz concentration camp and Holocaust perpetrator