The Kenya Red Cross and Machakos County firefighters responded to a fire incident at Katoloni Mixed Day and Boarding Secondary School last night.
The fire broke out some minutes after 9pm.
Red Cross said they managed to give first aid to affected students.
It was not yet clear what triggered the fire.
Unconfirmed reports indicated some students had been rushed to Machakos Level 5 hospital after they inhaled smoke.
This comes as the country witnesses worrying trend of school fires.
On September 6 a fire broke out at Hillside Endarasha Academy in Nyeri, killing 21 students.
A building on fire at Katoloni secondary school.
Since then, about a dozen cases have been occurred in a number of secondary schools.
On Wednesday fire gutted down part of Wami Secondary School in Kambi Garba, Isiolo.
In the Rift Valley, separate fires destroyed dormitories at at Irbaan Primary School and Naivasha High School.
A dormitory at Isiolo Boys High School went up in flames and a similar incident occurred at Mbooni High School in Makueni where a building was destroyed.
Students at Katulani Mixed Secondary School and Kalimani Mixed Secondary School in Kitui went on a rampage, destroying the school property.
Kenya Red Cross responders extinguishing fire.
At Buriuri Boys High School in Meru, two dormitories were destroyed by fire.
Authorities foiled arson attempt at Mukurweini Boys High School in Nyeri.
