This study analyses the Portuguese Corporate Income Tax (CIT) exemption provided under Article 53 of the Tax Benefits Code (TBC). This exemption applies exclusively to entities responsible for managing integrated systems of specific waste flows, such as packaging, tyres, used oils and electronic equipment, batteries and accumulators, and end-of-life vehicles. Duly licensed under the General Waste Management Regime (WMR), these entities benefit from tax exemption on reinvested profits or those allocated to legally designated purposes. The results show that, between 2013 and 2022, this exemption was used by the eligible entities despite the amounts claimed annually being relatively modest compared to the total tax benefits granted by the Portuguese government. This may be attributed to the limited number of entities eligible, given the legal requirement for licensing under the WMR, and to the narrow scope of the benefit itself, which applies only to profits that are either reinvested or allocated to legally defined purposes. Nevertheless, this measure has the potential to contribute to the sector’s economic competitiveness, ensuring reinvestment in technology and more efficient processes, strengthening beneficiary entities’ role in promoting the circular economy and the implementation of the European Union directives for waste management. It will also specify the Portuguese tax system's ability to integrate environmental objectives into public policies, highlighting the relevance of extra-fiscal instruments in driving the green transition and supporting the achievement of the global Sustainable Development Goals (SDGs).