Jefferson Township is one of fifteen townships in Wayne County, Indiana, United States. As of the 2010 census, its population was 3,482 and it contained 1,514 housing units.
Jefferson Township was organized in 1834.
According to the 2010 census, the township has a total area of , of which (or 99.82%) is land and (or 0.18%) is water. The streams of Awl Branch, Bat Branch, Bear Creek, Brick Creek, Civil Run, Hartley Run, Morgan Creek, Nettle Creek, Price Creek, Ulrich Creek, Value Run, West Lawn Run and White Branch run through this township.
The township contains eight cemeteries: Olive Branch, Brick Church, Ulrich, St. Jacobs Lutheran, Felton Family, Baldridge, Unnamed, and West Lawn.
Jefferson Township is served by the Hagerstown-Jefferson Township Public Library.