The right to education is globally acknowledged as a basic human right. Education is regarded as the primary vehicle by which economically and socially marginalized persons can break vicious cycle of poverty. In Kenya, the right to education is provided for in article 53(b) of Kenya Constitution, which advocates for the right to free and compulsory basic education for every child. Article 54 of the Constitution of Kenya emphasizes the need to enhance education for persons with disabilities. The Government of Kenya recognizes the importance of Special Needs Education as a crucial sub sector for accelerating the attainment of Education For All, Millennium Development Goals and Sustainable Development Goals. The objective of the study was to establish teacher based opportunities and challenges influencing education for the mentally challenged learners. The study established that teacher-based opportunities influencing education for the mentally challenged learners are: qualified teachers, teacher’s attitude, special school allowance for teachers, teacher-pupil ratio, teachers’ skill, motivation, gender and teachers’ experience. Teacher-based challenges include: level of retardation of learners, availability of qualified teachers, teacher’s attitude, special school allowance for teachers, teacher-pupil ratio, teachers’ skill, motivation, teachers’ experience. It was concluded that learners are accorded various opportunities to participate in learning but there was an array of challenges too. The study recommended that school management and the ministry of education should establish strategies to ensure that learners and teachers are motivated and facilitated to foster quality education for the mentally challenged. This information is valuable to policy makers with regard to promotion of special education in Kenya.