Manufacturing firms in Nigeria face mounting pressure from rising energy costs, environmental regulations, and global demand for sustainability. This study qualitatively investigates how GMPs influence the growth trajectories of manufacturing firms in Edo North, Edo State, Nigeria. Multiple case studies of 24 firms across lime stone and cement manufacturing, agro-processing, food processing, quarrying, sawmilling, fish processing, light fabrication, and packaging, among others, are used. Data were collected through interviews with firm leaders, site observations, and document reviews between September 2025 and March 2026. Green manufacturing practices serve as significant catalysts for firm growth in Edo North by reducing operational costs, improving quality, gaining regulatory and reputational benefits, and opening new market opportunities. However, the study concludes that the benefits of adopting green manufacturing are not evenly realized, largely because of contextual constraints in infrastructure, finance, technical capacity and regulatory environments. The government at all levels, especially the Edo State government, should provide tax rebates and low-interest green loans to manufacturers adopting energy-efficient machinery and renewable energy systems.