St. Martin Kathonzweni School began in 1970 as a Harambee Day School. It was established on land that was hewn from that of Kathonzweni HGM Primary School. At the time, it was a mixed school and had only 15 students. The school was run by the local community but was later adopted by the Catholic Church under the Catholic Diocese of Machakos as the sponsor. From 1986 to 1989, the school hosted A-level classes, mainly in art subjects. During that period, the school sent many students to the university and a significant number of others to middle level colleges. The school management decided to transform the school into a boys’ boarding school in the 1990s. It was re-registered in 2007 and the phasing out of girls was done from 2008 to 2010. In 2017, it was registered as a four streamed extra county school and rebranded St. Martin Kathonzweni School in keeping with the tradition of the Catholic Church to name the schools it sponsors after saints. Currently, the school is an extra county boys’ boarding school with a population of 800 students. It has also been designated as a STEM (Science, Technology, Engineering and Mathematics) school by the MOE. The school is located in Kathonzweni Township, the headquarters of Kathonzweni Sub County, 23km from Wote along the Wote-Makindu road.