Waste management includes those activities and actions required to manage wastes from inception to its final disposal. These include collection, transport, treatment and disposal of waste together with monitoring and regulation of waste management process. Inadequate and inappropriate knowledge of handling of horticultural wastes may have serious health implications and a significant impact on the environment as well. This is so because, if people possess good knowledge towards waste management, they can protect themselves from infectious diseases and keep the environment clean. This affects people’s attitude and most people due to lack of capacity or training on how to handle wastes, do not bother to dispose wastes appropriately. This study therefore, assesses the influence of capacity building on waste management amongst horticultural processing Micro, Small and Medium Enterprises (MSMEs) in Kenya. Using descriptive research design, the data were collected using structured questionnaires from 31 Certified Horticultural processing MSMEs in Kenya derived from Nairobi, Central and Western regions after undergoing various trainings on waste management. The results indicated that the majority of those engaged in horticultural processing MSMEs business are married (90.3%), affirming the family-oriented business tier. Further, the results showed that, before conducting training to the MSMEs, their level of knowledge on reduction in quantity of waste, waste management was at 58% and 68%, respectively. After training the result showed a high level of improvement at 87% and 83.9% on the same variables. The results further showed changes on waste management before and after capacity building with a mean of 9.29 and 16.70 respectively. Therefore, the study established a significant relationship with a p-value of 0.000 between capacity building and waste management in horticultural processing MSMEs in Kenya.