Participatory budgeting involves participation of ordinary citizens in the allocation of public resources and therefore contributes to deepening democracy in any nation both at the central government and decentralized units. The Constitution of Kenya 2010 and various legal instruments have anchored and institutionalized public participation in management and allocation of public resources. Makueni County has implemented participatory budgeting which has been praised as a model for participatory budgeting in the country. There is however, gap on the performance of the county government and there is thus need to study the influence of participatory budgeting on the performance of county governments. This study focus on Makueni County, Kenya. The specific objectives of the study were to: assess how government structure influence county performance and; the extent to which methodology of delivering participatory budgeting affect performance of the county. The study population was 562,420 citizens of Makueni County who are above 18 years of age (eligible participants in public participation forums) spread across the 30 wards. The study sampled 400 respondents. The data was collected by use of a questionnaire and secondary data from the County Government of Makueni on participatory budgets and projects. The data was analyzed through descriptive and inferential statistics. The results show that the government environment and structure (β1 = 0.486, t = 9.10, p = 0.000), the methodology (β3 = 0.548, t = 13.754, p = 0.000), had a positive influence on the performance of county government. The study found that the government environment has a positive influence on the performance of the county governments. The study therefore recommends that; the county government to establish a legal framework to entrench and deepen the participatory planning and budgeting process to ensure the government environment is conducive for improved service delivery.