Abstract: This research aims to investigate the influence of infrastructure in the implementation of competency-based curriculum in the Catholic private primary schools in the Catholic Diocese of Homa Bay, Kenya. The study was anchored on the Constructivist Theoretical Framework advanced by Lev Vygotsky in 1934. The study employed mixed methods research design where qualitative and quantitative approaches were employed. The quantitative method utilized a cross-sectional design while the qualitative adopted a phenomenological research design. The study targeted all 25 schools, 25 head teachers, 325 teachers of grades 1-6, and 2 education secretaries. cluster sampling was employed to sample 13 schools, and 13 headteachers were automatically included. Using stratified random sampling, 98 teachers were sampled while 2 education secretaries were chosen using purposive sampling. Quantitative data collection employed questionnaires while qualitative data employed interview guides. From the data analyzed, it was evident that there were positive findings which revealed that sports and outdoor facilities were adequate while, there was also availability of educational software to facilitate CBC implementation. Findings of the study also confirmed that classrooms, laboratories and laboratory equipment, projectors, and learning equipment were insufficient and inadequate to facilitate the implementation of CBC. The study recommended that the school infrastructure be improved, equip classrooms and laboratories, and provide essential learning tools such as computers and projectors. Collaboration among different donors be encouraged, and regular infrastructure assessment conducted which would establish the gaps and work on them. Training teachers on using new tools and engaging the community in infrastructure support are essential for creating an effective learning environment and achieving successful CBC implementation 

Key Words: Infrastructure, Competency Based Curriculum, Implementation, Teaching/Learning Resources, School Environment