This study was set to investigate the influence of teachers' competency on the integration of ICT in teaching and learning in public secondary schools in Machakos County. The study hypothesis was that: There is no significant relationship between teacher competency and the integration of ICT in teaching and learning. The study used a sample of twenty one (21) secondary school head teachers and one hundred and twenty six (126) teachers. The study used questionnaires to collect data. Data were analyzed using descriptive and inferential statistics. The study established that majority of the head teachers and teachers had basic ICT literacy while only a few head teachers and teachers integrate ICT in teaching and learning due to their limited competency in ICT skills. The study findings showed a significant relationship between teacher competency and ICT integration. The study recommended that there is need for secondary school teachers to be trained in ICT integration in their subject areas in teaching and learning. The study also recommended that the Ministry of Education should ensure that all teachers train in ICT so as to acquire skills for teaching and learning.