The crash happened just after midnight on the highway between the capital Kampala and the northern city of Gulu, Reuters reported.
Initial investigations suggest it was caused by two buses coming from opposite directions trying to overtake other vehicles, a lorry and a sport utility vehicle (SUV).
"In the process both buses met head-on during the overtaking manoeuvres," the Uganda Police Force said in a statement on X. "Sixty-three people lost lives, all occupants from involved vehicles".