STORY: The landslide, caused by strong rains, hit the vehicle between the villages of Pueblo Rico and Santa Cecilia in Risaralda province, about 230 km (140 miles) northwest of the capital Bogota.
Colombia's President Gustavo Petro described the incident as a tragedy in a Twitter message.
The bus was traveling from Cali, Colombia's third largest city, to the municipality of Condoto, in Choco province.
Colombia had been hit by an unusually heavy rainy season, blamed on the La Nina weather phenomenon.
Events linked to heavy rains have killed more than 216 people and left 538,000 homeless so far in 2022, according to government statistics. Another 48 people are still missing across the country, the figures show.