Dieter Althaus (born 29 June 1958 in Heiligenstadt/Eichsfeld) is a German politician of the Christian Democratic Union (CDU).

Althaus was a teacher for Physics and Mathematics at the Polytechnic Secondary School in Geismar, Thuringia, from 1983 to 1989, where he became deputy headteacher in 1987.

On 5 June 2003 Althaus was elected Minister President of Thuringia; he succeeded Bernhard Vogel, who had resigned for reasons of age.

Althaus was also part of the CDU/CSU team in the negotiations with the SPD on a coalition agreement following the 2005 federal elections,[1] which paved the way to the formation of Chancellor Angela Merkel’s first government.

[4] Althaus caused a skiing collision in Styria, Austria on 1 January 2009 in which he suffered severe injuries.