ABSTRACT
This research was conducted to detennine the factors affecting teacher's implementation of educational intervention in regular primary schools in Mirui zone East Karachuonyo Division Rachunyo district of the republic of Kenya. There are 17 primary schools of which 9 were randomly sampled to be target schools for the study. In the 9 sampled schools 65 teachers were found be present. Only 8 teachers have qualified to have qualified to handle learners with disabilities in regular primary schools. 28 learners were identified to be learners with mental retardation learning alongside other normal learners. The research targeted the teachers and school administrators for more information on factors affecting the implementation of educational intervention for learners with mental retardation in regular primary school setting. The tools used were oral interviews and questionnaires for the teachers and head teachers. The data collected and interpreted revealed that these categories of learners are found in regular primary schools. It was also found that teachers are faced with a lot of challenges when implementing educational intervention for learners with mental retardation. These learners do not get the quality of education they deserve due to several factors within and outside the school. The researcher therefore recommended that head teachers, teachers, and parents should work together as a team to solve some of the challenges. The government should also be made aware of the challenges and their input sort. More incentives should be availed to teachers so as to have more teachers trained to handle learners with special needs in regular primary school.