Thomassen is a patronymic family name of Scandinavian and Dutch origin. It literally means "son of Thomas", i.e., approximately corresponds to Thomson. Notable people with the name include:

• Ann-Mari Thomassen (born 1964), Sámi politician
• Bjørn Thomassen (born 1968), Danish anthropologist and social scientist
• Carsten Thomassen (mathematician) (born 1948), Danish mathematician
• Carsten Thomassen (journalist) (1969–2008), Norwegian journalist and war correspondent
• Dag Ole Thomassen (born 1986), Norwegian football goalkeeper
• Dan Thomassen (born 1981), Danish football defender
• Einar Thomassen (born 1951), Norwegian Professor in Religious Studies
• Gustav Thomassen (1862–1929), Norwegian actor and theatre director
• Hedvig Mollestad Thomassen (born 1982), Norwegian jazz musician
• Ivar Thomassen (1954–2016), Norwegian folk singer, songwriter, and jazz pianist
• Jacques Thomassen (born 1945), Dutch organizational theorist
• Joachim Thomassen (born 1988), Norwegian football defender
• Jordy Thomassen (born 1993), Dutch football striker
• Kay Thomassen (born 1987), Dutch football midfielder
• Knut Thomassen (1921–2002), Norwegian actor and theatre director
• Magne Thomassen (born 1941), Norwegian speed skater
• Mariann Thomassen (born 1979), Norwegian musician from the rock band Surferosa
• Martijn Thomassen (born 1990), Dutch football defender
• Mikkjal Thomassen (born 1976), Danish field hockey player
• Mogens Thomassen (1914–1987), Danish field hockey player
• Petter Thomassen (1941–2003), Norwegian Conservative Party politician
• Reidar Thomassen (1936–2024), Norwegian writer
• Thomas Thomassen (1878–1962), Norwegian actor and theatre director
• Turid Thomassen (born 1965), Norwegian Red Party politician
• Wim Thomassen (1909–2001), Dutch politician

Surname list

This page lists people with the surname Thomassen.
If an internal link intending to refer to a specific person led you to this page, you may wish to change that link by adding the person's given name(s) to the link.