Harmony Township is one of ten townships in Posey County, Indiana. As of the 2020 census, its population was 1,245.
Harmony Township was organized in 1821. A large share of the first settlers being Harmonites caused the name to be selected.
The James Elliott Farm and New Harmony Historic District are listed on the National Register of Historic Places.
It is within the Metropolitan School District of North Posey County, which operates North Posey High School.
New Harmony Town and Township Consolidated Schools consolidated into MSD of North Posey County as of 2012.