Penn Township is one of twelve townships in Jay County, Indiana, United States. As of the 2020 census, its population was 1,133 (down from 1,239 at 2010) and it contained 530 housing units.
Penn Township was named in honor of William Penn.
The Rebecca Rankin Round Barn was listed on the National Register of Historic Places in 1993.
According to the 2010 census, the township has a total area of , of which (or 99.93%) is land and (or 0.07%) is water. The streams of Brooks Creek and Haines Creek run through this township.
The township contains three cemeteries: Hillside, Maple Lawn and West Grove.