Grant Township is one of fifteen townships in Greene County, Indiana, USA. As of the 2020 census, its population was 682, down from 739 at 2010.

Historical population

Census	Pop.	Note	%±
1890	1,006		—
1900	1,099		9.2%
1910	1,009		−8.2%
1920	973		−3.6%
1930	898		−7.7%
1940	867		−3.5%
1950	731		−15.7%
1960	715		−2.2%
1970	668		−6.6%
1980	764		14.4%
1990	704		−7.9%
2000	690		−2.0%
2010	739		7.1%
2020	682		−7.7%
Source: US Decennial Census

According to the 2010 census, the township has a total area of 24.61 square miles (63.7 km), of which 24.59 square miles (63.7 km) (or 99.92%) is land and 0.03 square miles (0.078 km) (or 0.12%) is water. The stream of Buck Creek runs through this township.

• Switz City (west three-quarters)

• Smith Township (north)
• Fairplay Township (east)
• Washington Township (southeast)
• Stafford Township (southwest)
• Stockton Township (west)
• Wright Township (northwest)

The township contains three cemeteries: Buzan, Switz City and Waggoner.

• SR 54
• SR 67

• "Grant Township, Greene County, Indiana". Geographic Names Information System. United States Geological Survey, United States Department of the Interior. Retrieved September 24, 2009.
• United States Census Bureau cartographic boundary files

• Indiana Township Association
• United Township Association of Indiana