Horst Posdorf (8 February 1949 in Dornum – 12 October 2017) was a German politician and a Member of the European Parliament (2005-2009).
He was a member of the Committee on Development and the delegation for relations with Arab states of the Persian Gulf, including Yemen.
He was also a substitute for the Committee on the Internal Market and Consumer Protection, the delegation for relations with the countries of Southeast Asia and the Association of Southeast Asian Nations, and the delegation to the ACP-EU Joint Parliamentary Assembly.
He worked as a probationary teacher in 1974 and 1975, as a teaching inspector in 1975, and as an academic employee at the computer center of Ruhr University Bochum from 1976 to 1978.
Horst Posdorf was a member of the North Rhine-Westphalia Land Assembly from 1985 to 2000.