| Official Name: | Union Township Gibson County |
| Settlement Type: | Township |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Indiana |
| Subdivision Type2: | County |
| Subdivision Name2: | Gibson |
| Subdivision Type3: | Township Seat |
| Subdivision Name3: | Fort Branch |
| Subdivision Type4: | School District |
| Subdivision Name4: | South Gibson School Corporation |
| Government Type: | Indiana township |
| Leader Title: | Trustee |
| Leader Name: | Brenda Sollman |
| Area Total Sq Mi: | 50.43 |
| Area Land Sq Mi: | 50.31 |
| Area Water Sq Mi: | 0.12 |
| Population As Of: | 2020 |
| Population Total: | 4399 |
| Population Density Sq Mi: | auto |
| Timezone: | CST |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Elevation Footnotes: | [1] |
| Elevation M: | 139 |
| Elevation Ft: | 456 |
| Coordinates: | 38.2464°N -87.5553°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 47648 |
| Area Code: | 812 |
| Blank Name: | FIPS code |
| Blank Info: | 18-77300[2] |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 453916 |
| Named For: | The Union |
Union Township is one of ten townships in Gibson County, Indiana. As of the 2020 census, its population was 4,399 (up from 4,197 at 2010[3]) and it contained 1,938 housing units,[4] more than 90% of which live either within or in areas adjacent to the town of Fort Branch. Fort Branch is the township seat. Nearly all of the Toyota Motor Manufacturing Indiana Complex is located within Union Township.
Union Township was established in 1890.[5]
According to the 2010 census, the township has a total area of, of which (or 99.76%) is land and (or 0.24%) is water.[3]
The township contains three cemeteries: Durham, Mount Mariah and Walnut Hill.
Union Township is the center of the South Gibson School Corporation.