To promote participation and access to education, the government introduced free primary education. The introduction of FSE has resulted into increased enrolment at all levels which has been blamed for the poor performance of pupils in public primary school of Imenti Central District. The current study sought to determine the impact of enrollment on the quality of learning in primary schools in Imenti Central District. The study employed the descriptive survey research design. Purposive sampling was used to select 2 QASO officers in charge of Imenti Central district; giving a sample size of 382 participants. Questionnaires and interview schedules were used as tools for data collection. Data was analysed using descriptive statistics. The results of data analysis were presented using frequency distribution tables and bar graphs. The study established that high enrolment trends in primary schools led to overworking the staff members, inadequate teaching and learning facilities, poor sanitation facilities and inadequate classroom. The increased enrolment impacted to a great extent on the quality of learning in public primary schools. Based on the findings of the study, it is recommended that the government puts measures in place to avail facilities that match the pupils' enrolment.