Brownstown Township is one of twelve townships in Jackson County, Indiana, United States. At the 2020 census, its population was 5,664 and it contained 2,318 housing units.
Brownstown Township was organized in 1817, and took its name from Brownstown, the county seat. Shields' Mill Covered Bridge was listed on the National Register of Historic Places in 2016.
According to the 2010 census, the township has a total area of , of which (or 98.59%) is land and (or 1.41%) is water. The streams of Ballard Creek, Hough Creek, Kiper Creek, Spray Creek, West Branch White Creek and White Creek run through this township.
The township contains ten cemeteries: Burrell, Durland, First German Presbyterian, Miller, Robertson, Saint Pauls, Smallwood, Wayman, Weathers and Woodmansee.
Brownstown Township residents may obtain a free library card from the Brownstown Public Library in Downtown Brownstown.