| Official Name: | Janesville Township |
| Settlement Type: | Township |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Kansas |
| Subdivision Type2: | County |
| Subdivision Name2: | Greenwood |
| Area Total Km2: | 373.07 |
| Area Land Km2: | 370.74 |
| Area Water Km2: | 2.33 |
| Area Total Sq Mi: | 144.04 |
| Area Land Sq Mi: | 143.14 |
| Area Water Sq Mi: | 0.9 |
| Area Water Percent: | 0.62 |
| Population As Of: | 2000 |
| Population Total: | 548 |
| Population Density Km2: | 1.5 |
| Population Density Sq Mi: | 3.8 |
| Elevation M: | 337 |
| Elevation Ft: | 1106 |
| Coordinates: | 37.9847°N -96.1961°W |
| Blank Name: | GNIS feature ID |
| Blank Info: | 0474443 |
Janesville Township is a township in Greenwood County, Kansas, USA. As of the 2000 census, its population was 548.
Janesville Township covers an area of 144.04sqmi and contains one incorporated settlement, Hamilton. According to the USGS, it contains four cemeteries: Homer Creek, Ott, Prairie Chapel and Township.
The streams of Homer Creek, Indian Creek, Onion Creek, Slate Creek and Willow Creek run through this township.
Janesville Township contains one airport or landing strip, King Ranch Airport.