Osage Township is a township in Becker County, Minnesota, United States. The population was 774 as of the 2000 census.
Minnesota State Highways 34 and 225 are two of the main arterial routes in the township.
According to the United States Census Bureau, the township has a total area of 35.8 square miles (92.8 km²), of which 34.9 square miles (90.4 km²) is land and 0.9 square miles (2.4 km²) (2.57%) is water. The Straight and Shell Rivers flow southeastwardly through the township.