The preference and competitiveness of auto-garages is mostly dependent on their ability to perform well in dimensions such as quality of service delivery, cost, time taken to service a car, innovation and flexibility to adapt to variations in the environment. This study was motivated by the need to establish the influenced of monitoring and evaluation on performance of auto-garages in Nairobi, Kenya. The study was guided by the research questions aimed at examining how monitoring and evaluation influence the performance of auto-garages in Nairobi, Kenya. The study was anchored on Goal-setting theory. The study population was the registered auto-garages in Nairobi, Kenya. The target population was 410 employees in 82 registered auto-garages in Nairobi, Kenya. A simple random sampling technique was used to sample 202 auto-garage workers for quantitative data; purposive sampling to sample 7 managers, 7 supervisors of mechanics and 1 county official and simple random sampling for 5 clients for triangulation purposes yielding to a sample size of 222. The study achieved a response rate of 92.79% equivalent to 206 employees. The study used primary data for quantitative and qualitative data which was collected using structured and unstructured interviews. Qualitative data was analysed thematically according to the research questions in a narrative form. Quantitative data was analysed using descriptive statistics for frequencies and Pearson Correlation using Statistical Package for Social Sciences at 5% level of significance. The research also adopted the regression model to test and assess the correlation among variables to predict the performance of registered auto-garages in Nairobi, Kenya. Analysed data was presented using figures, tabulations and charts to display the information. The research found out that with the use of monitoring and evaluation, there is always better performance of auto garages. The study recommended that garages should have modern diagnostic tools and digital platforms, as well as better monitoring and evaluation programs and systems in place to track progress. Keywords: Performance, Monitoring, Evaluation. Auto-Garages, Nairobi