The Technical and Vocational Education and Training (TVET) institutions are important in the development of skills in renewable energy, but the successful integration of solar PV systems within their curricula relies on the competence and qualifications of trainers. The study employed a sequential explanatory mixed method design to investigate the impact of trainers' competence on the integration of solar PV into the curricula of the TVET institutions in Uasin Gishu County, Kenya. Questionnaires were used to collect quantitative data and analyzed descriptively, and interviews were used to collect qualitative data and analyzed thematically. Results indicated that trainer qualifications significantly affect solar PV curriculum integration, as revealed by the regression model with significant findings of trainer qualifications ((β = −0.678, p < .01) trainer and trainees (β = -0.813, p < 0.001). The qualitative results showed that the inadequate specialized training in solar PV, limited continuous professional development, and limited exposure to industry were major constraints in successful integration. From the study findings, the recommendations are, specialized training of trainers, continuous training of trainers and increased industry-institution collaboration, coupled with policy and institutional interventions should be improved to enhance the integration of solar PV in the TVET curriculum.