The US National Park Service said the teenager was attacked by the animal on Friday on a hiking trail near the park's Old Faithful Geyser when she stopped for a photo.
"The girl turned her back to the bison to have her picture taken when the bison lifted its head, took a couple of steps and gored her," a statement said.
The exchange student, who is staying with a US family, was later airlifted to hospital for treatment. She was not identified.
"Visitors are reminded that Yellowstone wildlife is wild," the statement said.
"Wildlife should not be approached, no matter how tame or calm they appear.
"Bison can sprint three times faster than humans can run and are unpredictable and dangerous.