The successful integration of Information and Communication Technology (ICT) into Competency-Based Education (CBE) depends largely on teachers' technological knowledge acquired through continuous professional development. However, despite substantial investments in ICT infrastructure and teacher training in Kenya, the extent to which teachers' technological knowledge contributes to ICT integration in CBE classrooms remains inadequately understood, particularly in marginalised regions such as Turkana County. This study examined the relationship between teachers' acquisition of technological knowledge through professional development and the level of ICT integration in Competency-Based Education classrooms in public primary schools in Turkana County, Kenya. The study was anchored on the Technological Pedagogical Content Knowledge (TPACK) framework and adopted a mixed-methods research design incorporating both quantitative and qualitative approaches. The target population comprised 2,193 teachers, 487 headteachers, and 19 Curriculum Support Officers (CSOs). Purposive and stratified random sampling techniques were used to select study participants. Data were collected using teacher questionnaires, interviews with headteachers and CSOs, and classroom observation schedules. Quantitative data were analysed using descriptive and inferential statistics with SPSS Version 28, while qualitative data were analysed thematically. The findings revealed a statistically significant positive relationship between teachers' acquisition of technological knowledge through professional development and ICT integration in Competency-Based Education classrooms (β = 0.174, p = 0.006). The results indicate that teachers who possess higher levels of technological knowledge are more likely to integrate ICT effectively into classroom instruction. The study concludes that strengthening teachers' technological knowledge through continuous, practical, and context-specific professional development is essential for enhancing ICT integration in CBE classrooms. The study recommends that the Ministry of Education, the Teachers Service Commission, and school management should strengthen continuous ICT-focused professional development programmes, provide opportunities for hands-on technology training, and establish sustained technical support systems to enable teachers to effectively integrate ICT into classroom instruction. The findings contribute to the growing body of knowledge on teacher professional development and provide evidence to inform policies and interventions aimed at strengthening technology-enhanced teaching and learning in Competency-Based Education.