The bus was carrying 26 tourists and a driver when the accident occurred about 4:10 p.m. Thursday. The bus was traveling on U.S. 89 to Yellowstone National Park.
The 33-foot-long bus went off the pavement and the driver overcorrected, causing the bus to flip on its side and slide, authorities said.
Park spokeswoman Jackie Skaggs said Friday that most of the passengers were from China. She didn't know what other countries the passengers might be from but said all were from Asia.
The bus belonged to Salt Lake City-based Roaming America Travel Inc., Skaggs said. Messages left with the company weren't immediately returned Saturday.
It's not uncommon for bus companies to rent their vehicles to tour companies, but it's unclear whether that was the case in Thursday's accident, Skaggs said.
No citations have been issued, but the accident remains under investigation, she said.
Skaggs said she had no information on whether the tour continued or whether it was disbanded.
Connelly said the last she heard on Friday was that the group hadn't decided what to do next but the group had a new bus to use.