A deputy principal of Kirimara Boys High School in Nyeri is nursing injuries at Karatina Nursing Home after he was assaulted by rioting students.
Mr Linus Muna was injured by the rioting students on Tuesday night while on duty.
"I was going on with my normal duties when the students attacked me with stones," he told journalists.
The incident happened at around 8pm.
During the fracas, another teacher Emmanuel Korir was injured and sustained slight bruises, the hospital confirmed.
At least 23 boys were on Tuesday charged with three counts including assaulting and causing bodily harm to the teachers and malicious destruction of school property worth Sh700,000.
The boys who were arraigned at a Karatina court denied the charges and were released on Sh100,000 cash bail or Sh200,000 bond.
Elsewhere, Karatina Girls Secondary School, also in Nyeri, has been closed indefinitely.
County Director of Education Moses Makori said the students boycotted exams.
At the same time, ten boys from Miiri Secondary School have been suspended for allegedly planning a strike.
However, learning is still going on at the school.