Tietjen is a German surname. Notable people with the surname include:
Bettina Tietjen (born 1960), German television presenter Friedrich Tietjen (1834–1895), German astronomer Heinz Tietjen (1881–1967), German conductor Henry Roland Tietjen (1891-1976), American Legislator (Utah) James J. Tietjen (1933–2016), American researcher and executive John Tietjen (1928–2004), American Lutheran clergyman, theologian
Other uses 2158 Tietjen, main-belt asteroid Wilhelm-Tietjen-Stiftung für Fertilisation, fertility research group
See also Tietjens