| Official Name: | Llallagua |
| Native Name: | Llallawa |
| Settlement Type: | Town |
| Pushpin Map: | Bolivia |
| Pushpin Label Position: | bottom |
| Pushpin Map Caption: | Location within Bolivia |
| Subdivision Type: | Country |
| Subdivision Name1: | Potosí Department |
| Subdivision Type2: | Province |
| Subdivision Name2: | Rafael Bustillo Province |
| Subdivision Type3: | Municipality |
| Subdivision Name3: | Llallagua Municipality |
| Subdivision Type4: | Canton |
| Subdivision Name4: | Llallagua Canton |
| Leader Title: | Mayor |
| Leader Name: | Tomás Quiróz (Without Fear Movement; elected 2010) |
| Leader Title1: | President |
| Leader Name1: | Maximo Urquieta Mitma (2007) |
| Unit Pref: | Imperial |
| Population As Of: | 2001 |
| Population Total: | 20065 |
| Timezone: | BOT |
| Utc Offset: | -4 |
| Coordinates: | -18.4167°N -101°W |
| Elevation M: | 3895 |
Llallagua (in hispanicized spelling) or Llallawa (Aymara for a monstrous potato (like two potatoes) or animal, Quechua for the god of seed-time during the Inca period) is a town in the Potosí Department in Bolivia. It is the seat of the Llallagua Municipality, the third municipal section of the Rafael Bustillo Province.
Llallagua features a rare microclimate amidst the semi-arid tundras of Potosí and Oruro, due to its extreme elevation near 4000m. Semi-arid and with average temperatures in its warmest month sitting right on the 11 °C threshold, the city's climate straddles that of the subtropical highland climate (Cwc, according to the Köppen climate classification), with subpolar oceanic characteristics and a cold semi-arid climate (BSk). Summers are cool and wet with daily highs rarely rising above 22 °C, while winters feature cooler days with much colder nights averaging −4 °C. These low temperatures are a result of the extreme precipitation deficit during the winter months with the resulting aridity leading to an increased diurnal temperature variation.