Thiel is a German-language surname. Notable people with the name include:
Adolf Thiel (1915–2001), German-American engineer
Alvar Thiel (1893–1973), sailor
Andreas Thiel (born 1960), German handball player
Andreas Thiel (bishop) (1826–1908), Catholic bishop of Ermland
Ben Thiel (born 1982), Australian Model, Golfer & Race Car Driver
Bert Thiel (1926–2020), baseball pitcher
Claudia van Thiel (born 1977), female volleyball player
Edward C. Thiel (1928–1961), geologist
Edwin Thiel (1913–1944), German Luftwaffe ace
Ernest Thiel (1859–1947), Swedish financier, art collector, and translator
Frans-Jozef van Thiel (1906–1993), Dutch politician
Heiner Thiel (born 1957), German sculptor and curator
Heinz Thiel (1920–2003), German film director and screenwriter
Jana Thiel (1971–2016), German sports presenter and journalist
Joachim Thiel (born 1951), German footballer
Jon Thiel (born 1975), rugby player
Lisa Thiel, a professional quizzer and regular panelist on UK quiz show Eggheads
Lucien Thiel (1943–2011), Luxembourgian politician
Marie-Jo Thiel (born 1957), French ethicist
Maximilian Thiel (born 1993), German professional footballer
Midori Kono Thiel (born 1933), Japanese American calligrapher
Otto Thiel (1891–1915), German football player
Peter Thiel (born 1967), American entrepreneur
Phil Thiel (born 1984), American rugby union player
Pieter J.J. van Thiel (1928–2012), Dutch art historian
Sten Thiel, Commissioner of the Svenska Scoutförbundet
Tamiko Thiel (born 1957), American media artist
Walter Thiel (1910–1943), German engineer
Walter Thiel (chemist) (1949–2019), German theoretical chemist
Yannic Thiel (born 1989), German footballer
Fictional characters
Frank Thiel, detective chief inspector in German television series Tatort Münster