Muang Xay
| Xay ເມືອງໄຊ Udomxai, Muang Xay | |
|---|---|
| Xay District | |
| Coordinates: 20°41′29″N 101°59′10″E / 20.69139°N 101.98611°E | |
| Country | Laos | 
| Province | Oudomxai | 
| Population  (2015) | |
|  • Total | 79,500 | 
| • Religions | Buddhism | 
| Time zone | UTC+7 (ICT) | 
| Website | www | 
Muang Xay (Lao: ເມືອງໄຊ, pronounced [mɯ́a̯ŋ sáj]), also referred to as Oudomxai or Oudomxay, is the capital city of Oudomxai Province, Laos.