Education is an important life process that plays a vital role in forming the foundation for a student’s future better being, as it equips learners with basic knowledge, skills and attitudes that will enable him/her to cope well in life. This study examined the factors that lead to increased school dropout among high school students in Kirinyaga County, with the aim of suggesting the possible solutions thus promoting learner’s retention among high schools. The objective of the study was to determine the factors leading to increased school dropout in Kirinyaga County. This study was undertaken in response to high school dropout rates and poor academic performance among the high school students in Kirinyaga County. In this study, questionnaires were used as data collecting instruments. Questionnaires were preferred because of their ability to ensure confidentiality to responses from respondents. A visit was done to 18 high schools, which are located in Kirinyaga, which will include both day and boarding.  Questionnaires were issued randomly to ensure fairness. 18 principals and 108 teachers. The entire questionnaire was returned hence equivalent to 100%. Responses received from questionnaires was organized, tabulated and analyzed using frequencies and percentages. Data was analyzed by use of Statistical Package for Social Sciences (SPSS). Findings were presented using frequency tables. This study established that low socio-economic status, poor school performance, drug and substance abuse, peer pressure among others contribute to student dropout. Poverty leading to financial problems was also cited as a cause of school dropout. The study recommends that the government should take stern measures against traders who employ children to pave way for these children to go to school. Similar studies should be done in the other counties so as to find a long lasting solution to the problem.