Theodorus Wilhelmus (Theo) Maassen (born 8 December 1966 in Oegstgeest, Zuid-Holland) is a Dutch comedian and actor who grew up in Zijtaart in the Dutch province of Noord-Brabant. In addition to his shows, he has also made a number of appearances in films.

Besides acting, he has done four solo cabaret shows so far; Bepaalde dingen (1994), Neuk het systeem (1996), Ruwe pit (1998) and Functioneel naakt (2002).

In July 2004 he released a rap song called Doodsbedreiging (Death threat), which is about his frustrations about the decreased freedom of speech in The Netherlands.