Harmony
- County:
- Butler County
- County Seat:
- No
- Area (mi²):
- 0.394
- State:
- Pennsylvania
Harmony is a borough located in Butler County, Pennsylvania. Harmony has a 2026 population of 918. Harmony is currently declining at a rate of -0.76% annually and its population has decreased by -3.37% since the most recent census, which recorded a population of 950 in 2020.