| Official Name: | Johannishus |
| Pushpin Map: | Sweden Blekinge#Sweden |
| Subdivision Type: | Country |
| Subdivision Name: | Sweden |
| Subdivision Type3: | Municipality |
| Subdivision Name3: | Ronneby Municipality |
| Subdivision Type2: | County |
| Subdivision Name2: | Blekinge County |
| Subdivision Type1: | Province |
| Subdivision Name1: | Blekinge |
| Area Footnotes: | [1] |
| Area Total Km2: | 0.96 |
| Population As Of: | 31 December 2010 |
| Population Total: | 748 |
| Population Density Km2: | 780 |
| Timezone: | CET |
| Utc Offset: | +1 |
| Timezone Dst: | CEST |
| Utc Offset Dst: | +2 |
| Coordinates: | 56.2167°N 40°W |
Johannishus is a locality situated in Ronneby Municipality, Blekinge County, Sweden with 748 inhabitants in 2010. Johannishus castle is situated some kilometers north of locality. There exist a school for 150 pupils and a library.
The locality is also seat of the Hjortsberga natur-& kulturförening (Hjortsberga nature and culture club). The club is recording and publishing information on the history of the localities Hjortsberga, Johannishus, Edestad, Förkärla and Listerby.