Capacity building emerged as the most influential factor for organizational growth. The research paper explores the effect of capacity-building initiatives by business associations such as the Kenya Association of Manufacturers (KAM) on the growth of member organizations within Kenya’s manufacturing sector. The research designs embraced a descriptive research design focusing on 534 member SMEs of KAM. Structured questionnaires were used to gather the primary data, which was assessed with help of multiple regression analysis. The results showed that there is a positive and statistically significant relationship between capacity-building programs and the growth of member organizations. The research concludes that association-led training and knowledge improvement programs enhance operational efficiency, innovation capability, and competitiveness of the members. It advises that business associations must make more investments into special trainings, mentorship, and collaboration with educational and technical institutions in order to reinforce the performance and longevity of the sector.