The Portage County Sheriff's Department said the crash occurred about 2:30 a.m. at the intersection of Highway 66 and Birchwood Lane, about 2 miles southwest of Stevens Point, Gannet Wisconsin Media reported.
Officers said the vehicle was engulfed in flames and nearby power lines were down when they arrived. One victim, a man, was thrown from the vehicle and the other two victims were found inside.
The victims' identities had not been released.
Authorities said alcohol was a possible factor in the crash, Gannett said.