Sainyabuli, is the capital of Sainyabuli Province, Laos. It lies on Route 4 which along with Route 13 connects it to Luang Prabang, roughly 80 kilometres northeast by road and to the Thai border across the Luang Prabang Range in the southwest. A passport control point is in the area. Sainyabuli Airport lies southwest of the town.

Sainyabuli province is a province in northwest Laos. Saiyabuli town is the capital of the province. Saiyabuli is the only Lao province that is completely west of the Mekong River.