Rietberg is a town in the district of Gütersloh in the state of North Rhine-Westphalia, Germany. It is located approx. 10 km south of Gütersloh and 25 km north-west of Paderborn in the region Ostwestfalen-Lippe. The town is located at the river Ems. There are 28,878 people living in Rietberg.