Corporate social responsibility (CSR) is an integral path towards realizing vision 2030 and the sustainable goals of the UN, as well as the sustainable development of individual countries. However, in recent years it has become increasingly clear that these goals cannot be achieved without sustainable corporate practices. Previous research seeking determine the effect of CSR on the financial performance of various institutions have yielded different results, leaving geographical, sectorial, and scholarly gaps. This study aimed to discover the effect of CSR on the financial performance of financial institutions in Kenya, as this country lacks a direct association between CSR and corporate financial performance (CFP). We focused on examining the effect of ethical, charitable, and gender-mainstreaming CSR activities on the financial performance of financial institutions in Kirinyaga County. A study population of 300 employees working in the financial institutions in Kirinyaga County was included, and a sample of 171 participants was selected using stratified and systematic sampling techniques. A causal research design was adopted, and data were analyzed using SPSS software. Questionnaires were administered in person to gather primary data. The study found a strong positive relationship between CSR practices and the financial performance of financial institutions and recommends that firms invest more in ethical, charitable, and gender-mainstreaming CSR activities, as such activities positively influence their financial performance.