Abstract: The study sought to investigate the influence of knowledge management systems on performance of small and medium enterprises. The study was anchored on systems theory. Descriptive cross sectional research design was adopted. Owners and employees of small and medium enterprises in Nanyuki town were targeted. Stratified random sampling technique was used to select a sample of 115 respondents. Data was analyzed using descriptive and inferential statistics and regression analysis was used to establish the relationships between the variables. The findings were presented in tables and figures. The findings showed that knowledge management systems were lowly adopted by SMEs especially for feedback and decision support systems. Knowledge management systems (p=0.11) was not found to be statistically significant. It was concluded that majority of managers and employees did not have awareness of these systems. Failure to adopt these systems therefore remains the gap in the performance of SMEs. The study recommended that SME owners and employees should be sensitized about knowledge systems to enable them adopt the same and enhance performance.