Open government data is data and information produced or commissioned by a government or government-controlled entities, available to all to help the public better understand what the government does and how well it performs, and to hold it accountable for wrongdoing or unachieved results. The purpose of this study was to investigate the role of open government data in improving public service delivery in the County of Nairobi. Specific objectives are: To examine the extent to which government’s open data availability influences public service delivery in the County; to examine the extent to which knowledge level on government’s open data influences public service delivery in the County; to examine the extent to which application of government’s open data influences public service delivery in the County of Nairobi. The research design applied was exploratory design to show the influence of open government data on public service delivery. The study targeted all thirteen County Government Sectors. The selected sample size from the target County Sectors was 172 employees. Out of the selected sample size, the researcher only managed to get a response from 132 employees (76.7%). The researcher used questionnaires as the main instrument for this study. The data were analyzed using descriptive analysis and multiple regression analysis to study the relationship between public service delivery and availability, knowledge level, and application of government open data. From the study findings, the availability of county government’s open data has the least influence in the role open data plays in public service delivery at the county. This is mainly affected by inadequate and non comprehensive open data platforms and inadequate requisite infrastructure and knowledge on the value of open government data. For the existing open data, datasets are not wide-ranging and do not cover all the areas of county service provision/mandate.