This study examined teacher related factors influencing students' enrollment in Biology subject in public secondary schools in Meru Central Sub County in Kenya. The study utilized the descriptive survey research design on a target population of 9,859 respondents consisting of 9,748 Biology students, 62 trained Biology teachers and 49 Heads of Science Department (HoDs) in the 49 public secondary schools in Meru Central Sub County. Stratified random sampling and purposive sampling techniques were employed to select a sample size of 355 respondents comprising of 345 form three and form four Biology students, five trained Biology teachers, and five Heads of Science Departments. The tools for data collection were questionnaires and interview schedules. The research instruments were validated by the help of research experts in the Department of Education, Chuka University. Spearman Brown Prophesy Formula was used to estimate the reliability of the instruments and a reliability coefficient of 0.79 was obtained. The data were analyzed using descriptive statistics facilitated by the Statistical Package for Social Sciences (SPSS) version 20. Based on the findings of the study it was concluded that teacher absenteeism, motivation level, workload, experience, instructional approaches and preparedness were teacher related factors that influenced students to enroll in Biology.