| Official Name: | Allendorf, Iowa |
| Settlement Type: | Unincorporated Community |
| Pushpin Map: | Iowa#USA |
| Subdivision Type: | Country |
| Subdivision Type1: | State |
| Subdivision Type2: | County |
| Subdivision Name2: | Osceola County |
| Timezone: | Central (CST) |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Elevation Ft: | 1598 |
| Coordinates: | 43.4147°N -95.6433°W |
| Postal Code Type: | Zip code |
| Postal Code: | 51354 |
| Area Code: | 712 |
| Blank Name: | GNIS feature ID |
| Blank Info: | 454138 |
Allendorf is an unincorporated community in Osceola County, Iowa, United States. It is located on Highway 59, five miles east of Sibley, at 43.413270N, -95.64318W,[1] adjacent to the Johnson Wilderness Area.
Allendorf was founded in 1895, possibly named after a town named Allendorf in Germany; the town was originally named Oliver.[2] Allendorf's population was 13 in 1902,[3] and 35 in 1925.[4] The population was 60 in 1940.[5]