Siegfried Neuenhausen (born November 30, 1931 in Dormagen) is a German sculptor, painter, graphic artist, author, editor, and realist sculptor.

Neuenhausen's works depict social contradictions, focus on socio-political themes, and use art to emancipate people. His depiction became more radical and political over the course of his career; for example, he placed figures of tortured and torsoless people in boxes, on chairs, and pinned them to wooden walls as leftover clothing. Neuenhausen staged moral appeals, such as the 1970 sculpture Man in a Box. His sculptures are about socio-political themes, exposing political lies, and denouncing violence, dictatorship, and torture. He worked with prisoners in Bremen and with the mentally ill on sculptures in Hamburg-Ochsenzoll and Wunstorf. For years, he has been revitalizing the local culture in Hanover-Hainholz. Together with graphic artist Klaus Staeck, Neuenhausen launched an initiative for the future German Chancellor Gerhard Schröder (SPD): In the election years of 1994, 1998, and 2002, as well as in 2005, artists donated works for an auction, the proceeds of which then funded the "Aus gegebenem Anlaß" art prize awarded by Schröder. Siegfried Neuenhausen signs some of his works with the monogram "S. N."