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.