| Grethel, Kentucky | |
| Settlement Type: | Unincorporated community |
| Pushpin Map: | USA Kentucky#USA |
| Pushpin Label: | Grethel |
| Pushpin Label Position: | left |
| Pushpin Map Caption: | Location within the state of Kentucky |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Kentucky |
| Subdivision Type2: | County |
| Subdivision Name2: | Floyd |
| Unit Pref: | Imperial |
| Population As Of: | 2000 |
| Population Density Km2: | auto |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation Ft: | 722 |
| Coordinates: | 37.4911°N -82.6478°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 41631[1] |
| Area Code: | 606 |
| Blank Name: | FIPS code |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 493369 |
Grethel is an unincorporated community located in Floyd County, Kentucky, United States.
A post office was established in the community in 1921, and named for the first postmaster's daughter.[2]