The purpose of this study was to examine the effect of innovation capabilities on performance of manufacturing firms in Nairobi City County, Kenya. The study was anchored on the positivist research philosophy and the non-experimental quantitative research methodology. The study employed the correlational, cross-sectional survey research design. The proportionate stratified random sampling technique was used to select a sample size of 228 manufacturing firms from a target population of 526 manufacturing firms in Nairobi City County, Kenya. A pilot study was conducted to test the validity and reliability of the constructed survey questionnaire. Through the drop and pick method, a cross-sectional survey-based approach was used to collect primary data from the manufacturing firms in Kenya. The collected data was processed and entered into the statistical package for social sciences (SPSS) version 26 to create a data sheet that was used for data analysis. The Pearson's product moment correlation analysis was performed to confirm or deny the relationship between the study variables. The Pearson's correlation analysis results indicated that product innovation capability, process innovation capability, marketing innovation capability and technological innovation capability had positive and significant relationship with performance of manufacturing firms in Nairobi City County, Kenya. A standard multiple regression analysis was performed with product innovation capability, process innovation capability, marketing innovation capability and technological innovation capability predicting the performance of manufacturing firms in Nairobi City County, Kenya. The regression results showed that product innovation capability, process innovation capability, marketing innovation capability and technological innovation capability had a positive and significant effect on performance of manufacturing firms in Nairobi City County, Kenya. The study recommended that it is imperative for the managers to implement innovation capabilities to foster the performance of manufacturing firms. Policy makers should consider initiating policy review to encourage stakeholders to implement innovation capabilities to foster the performance of manufacturing firms. The study points to several intriguing paths for future research.