Seneca Township is one of the fifteen townships of Noble County, Ohio, United States.

The 2020 census found 423 people in the township.

Located in the northern part of the county, it borders the following townships: No municipalities are located in Seneca Township, although the unincorporated community of Mount Ephraim is located in the township's northwest.

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,[4] 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.