Waldo Township is one of the fifteen townships of Marion County, Ohio, United States.

The 2020 census found 1,130 people in the township, 326 of whom lived in the village of Waldo.

Located in the southeastern corner of the county, it borders the following townships: The village of Waldo is located in western Waldo Township.

[4] The township is governed by a three-member board of trustees, who are elected in November of odd-numbered years to a four-year term beginning on the following January 1.

There is also an elected township fiscal officer,[5] who serves a four-year term beginning on April 1 of the year after the election, which is held in November of the year before the presidential election.