The road crash was reported on Tuesday from the district’s Gouripur Upazila, said police.
Around 1pm, the bus and the three-wheeler vehicle collided on the Mymensingh-Kishoreganj Highway at Ramgopal area, said Gouripur police OC Delwar Hossain.
Four people, including the auto-rickshaw’s driver, were killed on the spot, he said.
Two of them have been identified as Tarikur Rahman, 30, and Hero Mia, 40, according to the police officer.
Locals rescued two others from the scene and rushed them to the Mymensingh Medical College Hospital.