Bethlehem Township is one of fourteen townships in Cass County, Indiana. As of the 2020 census, its population was 745 (down from 795 at 2010) and contained 322 housing units.
Bethlehem Township was organized in 1836. It was named for an early settler's native hometown of Bethlehem, Pennsylvania.
According to the 2010 census, the township has a total area of , of which (or 99.86%) is land and (or 0.11%) is water.