Thelen may refer to:
People A. J. Thelen (born 1986), retired American professional ice hockey defenseman Albert Vigoleis Thelen (1903-1989), German author and translator Dave Thelen (born 1936), former Canadian Football League running back Eduard Thelen (born 1943), former German field hockey player Esther Thelen (1941-2004), American developmental psychologist Fanny Thelen (1856 - 1939), American clubwoman Frank Thelen (born 1975), German businessman Jodi Thelen (born 1962), American actress Kathleen Thelen, American professor Michael Thelen (1834–1918), German-American politician Nathan Thelen, one of the founding members of the band Pretty Girls Make Graves Paul Thelen, chairman and chief executive officer of Big Fish Games Robert Thelen (1884-1968), German aviation pioneer and designer Robert Thelen III, one of the founders of The Mendota Beacon Tim Thelen (born 1961), American professional golfer
Other uses Thelen LLP, a former American law firm Thelen Madagascar Frog, a common name for the frog Gephyromantis thelenae