PurposeThis study aims to investigate the intricate relationship between intellectual capital and environmental innovations among manufacturing medium and large firms in Uganda, utilizing the SmartPLS methodology.Design/methodology/approachThis research adopts a cross-sectional and quantitative approach, collecting data through a questionnaire survey from a sample of manufacturing medium and large (ML) firms in Uganda. The collected data underwent analysis to identify patterns and relationships using the SmartPLS structural equation modeling (SEM) technique.FindingsThe findings highlight a distinct pattern: structural capital is the strongest predictor of environmental innovations, with human capital being the next most significant factor. However, the positive relationship with relational capital did not attain statistical significance, suggesting the need for further exploration into inter-firm relationships.Practical implicationsFor managers, investing in robust organizational structures and human capital development programs can enhance firms’ capacity to drive eco-friendly initiatives, aligning with global sustainability agendas. Policymakers are encouraged to create an enabling environment that nurtures IC and incentivizes environmental innovation through supportive policies such as tax incentives and funding mechanisms for green technologies.Originality/valueThis study enriches the intellectual discourse on IC and environmental innovation by employing SmartPLS methodology to highlight the nuanced impact of its components, emphasizing the multifaceted nature of IC and its role in driving EI.