Washington Township is one of thirteen townships in Owen County, Indiana, United States. As of the 2020 census, its population was 6,387 (up from 6,164 at 2010) and it contained 2,616 housing units.

Washington Township was organized in 1819. It was named for George Washington.

The CCC Recreation Building-Nature Museum, McCormick's Creek State Park Entrance and Gatehouse, Secrest-Wampler House, and Stone Arch Bridge over McCormick's Creek are listed on the National Register of Historic Places.

According to the 2010 census, the township has a total area of 47.57 square miles (123.2 km), of which 47.4 square miles (123 km) (or 99.64%) is land and 0.17 square miles (0.44 km) (or 0.36%) is water. The White River defines the northeastern border of the township.

• Spencer

• Hancock Corner at 39°16′31″N 86°49′44″W / 39.275322°N 86.828896°W / 39.275322; -86.828896
• Highets Corner at 39°16′55″N 86°42′15″W / 39.28199°N 86.704171°W / 39.28199; -86.704171
• Romona at 39°19′38″N 86°43′48″W / 39.327268°N 86.730005°W / 39.327268; -86.730005
• Southport at 39°16′37″N 86°45′42″W / 39.276989°N 86.761673°W / 39.276989; -86.761673

(This list is based on USGS data and may include former settlements.)

The township contains these seven cemeteries: Blair, Chambersville, Mount Moriah, River Hill, Riverside, Rose and Witham.

• U.S. Route 231
• Indiana State Road 46
• Indiana State Road 67

• Miller Airport

• Spencer-Owen Community Schools

• State House District 46
• State Senate District 37

• "Washington Township, Owen County, Indiana". Geographic Names Information System. United States Geological Survey, United States Department of the Interior. Retrieved October 23, 2009.
• United States Census Bureau 2009 TIGER/Line Shapefiles
• IndianaMap

• Indiana Township Association
• United Township Association of Indiana
• City-Data.com page for Washington Township