<p>The call for environmental sustainability serves as a cornerstone for achieving global climate targets and ensuring a sustainable future for future generations. This study examined the environmental sustainability through the lens of labour productivity and human capital development in the Organisation for Economic Co-operation and Development (OECD) economies between 2000 and 2022. The study hinges on EKC using a battery of second-generation techniques and tracking the threshold or regime-dependent. Findings show that the amount of CO2 emissions has put OECD economies on the radar for implementing environmental preservation policies across all economic actors. Meanwhile, finding reveals that there is a negative impact of environmental financiers on environmental sustainability in OECD countries. In addition, the evidence shows that labour productivity and human capital development have a positive and significant impact on environmental sustainability in OECD countries. This study provides evidence that switching to greener forms of energy is an essential plan for ensuring environmental sustainability, where green finance, human capital development and labour productivity facilitate environmental sustainability at upper regimes. The study concluded that for environmental sustainability to spur economic development in OECD economies, OECD governments should coordinate expenses with environmental objectives, and this may reduce the dangers and help achieve long-term emission reductions.</p>