Conrad I, Count of Rietberg

Conrad I, Count of Rietberg (born after 1203, died 1284–1294), was a son of Count Henry II of Arnsberg. In 1237 he and his brother Godfrey III divided Arnsberg: Godfrey kept Arnsberg while Conrad received the Rietberg lands on the upper Ems and the family's Dutch holdings, making Rietberg a territory in its own right.

In the same year he married Oda of Lippe. He later joined the Teutonic Order and in 1264, after Oda's death in 1262, made the county over to their son Frederick I.