The pre-dawn accident happened in Makwanpur district's Basamadi area, about 120 kilometres from the capital, when the two buses crashed into each other along the national highway.
Ten people were killed and 30 others injured in the incident, officials said.
Twelve of the injured persons, who have been rushed to nearby Bharatpur Hospital, are said to be in critical condition, ekantipur news website reported today.
Police said a Russian was killed in the accident and was identified as a woman named Daria Mojkova.
