| Lan County | |
| Postal Code Type: | Postal code |
| Settlement Type: | County |
| Pushpin Map: | China Shanxi |
| Pushpin Label: | Lanxian |
| Pushpin Map Caption: | Location of the seat in Shanxi |
| Subdivision Type: | Country |
| Subdivision Name: | People's Republic of China |
| Subdivision Type1: | Province |
| Subdivision Name1: | Shanxi |
| Subdivision Type2: | Prefecture-level city |
| Subdivision Name2: | Lüliang |
| Population: | 148,315 |
| Population As Of: | 2020[1] |
| Population Density Km2: | auto |
| Coordinates: | 38.2794°N 111.6711°W |
| Timezone: | China Standard |
| Utc Offset: | +8 |
| P: | Lánxiàn |
| W: | Lan Hsien |
| Former names | |
| Also Known As: | Lanzhou |
| P2: | Lánzhōu |
| W2: | Lan-chou |
Lan County or Lanxian is a county under the administration of Lüliang City, in west-central Shanxi province, China.
Lanxian was formerly the seat of Lan Prefecture, during which time it was known as Lanzhou.