Decentralization in Kenya aimed to reduce bureaucratic delays and improve service delivery by transferring power to sub-national governments. Yet, governance challenges persist mainly due to unqualified staff, nepotism, cronyism, among others. The Kenya Institute for Public Policy Research and Analysis found 32% of county governments staff lack the required qualifications for their roles, leading to inefficiencies and service delivery gaps. Despite these concerns, no empirical research has explored the influence of human capital on the performance of Kisii and Kakamega county governments. This study addresses this gap by assessing the effect of human capital on performance of Kisii and Kakamega counties in Kenya. The study adopts a positivism research philosophy and a cross-sectional survey research design. The target population comprised of Chief officers, Directors and Assistant Director at various ministries, sub-county administrators and Members of County Assembly (N=325). To arrive at a statistically sound sample size, the study adopted the Yamane (1967) formula for sample size determination, which gives a sample size of 136 for Kakamega County and 92 for Kisii County (n=228). Given that the study is quantitative in nature, it adopts structured questionnaires in data collection, which were distributed using online platform (Google Forms). In data analysis, Stata version 17 was used to compute descriptive statistics (mean and standard deviation) and inferential statistics (Pearson correlation and univariate linear regression). Data was presented in prose form and visualized using tables and figures. Findings from the test of hypothesis using simple linear regression indicate that human capital has a statistically significant effect on performance (p<.05). Results revealed that human capital has a moderate positive association with performance, 𝑟 (191) =0.486, 𝑝<.05. It is recommended that the County Governments of Kisii and Kakamega should improve human capital by implementing performance contracting, eliminating political patronage, and investing in innovation infrastructure. Additionally, county governments should develop well-documented SOPs, ensure regular employee training, and embrace public participation to align policies with citizens’ needs.