The bus was on its way from the village of Potolo to the capital Sucre when it ran off the road near the town of Chataquila and plunged more than 100 meters, according to local media outlets.
Police are still investigating the cause of the most recent crash, the officials said.
Deadly bus accidents often take place on mountainous roads in Andean countries like Bolivia, Chile, and Peru.
On March 2, 21 people were killed when a public transport bus overturned and fell into an abyss on the highway linking the Bolivian departments of Cochabamba and Santa Cruz.
The bus was carrying students from the Universidad Pública de El Alto, which had suffered another tragedy that same day when a balcony collapsed at the college during a protest. (ILKHA)