Besides the eight pupils, who got injured in the crash, a manager of Trinity Academy also sustained injuries.
The driver of one of the two school buses was overtaking another vehicle during the head-on collision at Tokyo stage, an eyewitness, Grace Kanini, told The Standard.
The injured victims were taken to different hospitals in Kirinyaga West Sub-County.
"A female teacher, who had been trapped in the Trinity Academy bus, died on the spot," police said.
The body of the teacher was taken to Kerugoya County Referral Hospital morgue.
The wreckages of the two buses were towed to Sagana Police Station as investigations begin.