This study aimed to investigate the effects of corporate social responsibility (CSR) on the financial performance of microfinance institutions (MFIs) in Makueni County. The study was motivated by the increasing demand for openness and increased expectations that organizations measure, report, and gradually improve their CSR activities. A descriptive research design was used, and data was collected through a questionnaire, interviews, and case studies. The study used simple random sampling, stratified sampling, cluster sampling, and purposive sampling techniques to select a sample of 34 respondents from the target population of microfinance institutions in Makueni County. Descriptive statistics, correlation analysis, regression analysis, and thematic analysis were used to analyze the data. The findings of this study will be useful to MFIs in Makueni County, the Central Bank of Kenya, and other governing bodies and will help in theory building. The study's implications for policy and practice will be to provide an enabling environment and tax holidays to microfinance institutions that practice CSR. The study's research gap was on determining the impact of CSR on a firm's financial performance.