Rainer Robert Müller-Hörner (born 27 January 1967 in Fürth) is a retired male triathlete from Germany, who is best known for winning the European title in 1995.

Müller-Hörner was a professional athlete from 1984 to 1994.

He was awarded the Silbernes Lorbeerblatt, Germany's highest award for sporting achievement, in 2003.

He is married to Yvonne Hörner.

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