Ohio Township is one of nine townships in Spencer County, Indiana, United States As of the 2020 census, its population was 4,842 and it contained 2,207 housing units. Ohio Township contains the city of Rockport.
Ohio Township was first settled in about 1818.
According to the 2010 census, the township has a total area of , of which (or 99.22%) is land and (or 0.79%) is water.