| Conventional Long Name: | Eskilstunahus County |
| Native Name: | Eskilstunahus län |
| Common Name: | Eskilstunahus |
| Subdivision: | County |
| Nation: | the Swedish Empire |
| Year Start: | 1634 |
| Year End: | 1683 |
| S1: | Södermanland County |
| Flag S1: | Naval Ensign of Sweden.svg |
| Capital: | Eskilstuna |
| Title Leader: | Governor |
Eskilstunahus County, or Eskilstunahus län, was a county of the Swedish Empire from 1634 to 1683, named after the county seat of Eskilstuna House. It was one of three counties in the province of Södermanland, and in 1683 they were merged into the Södermanland County.