Green hydrogen technologies are increasingly recognised as a pivotal element in achieving a sustainable and low-carbon future. However, the full potential of green hydrogen to contribute to environmental sustainability can only be realised by integrating circular economy principles throughout its lifecycle. This paper presents a lifecycle assessment (LCA) of green hydrogen technologies, focusing on material efficiency, renewable energy integration, emissions reduction, and waste management. Through examining each stage—from production to end-use—the LCA highlights opportunities for reducing environmental impacts and enhancing resource recovery. In parallel, this paper proposes a policy strategy to promote circularity in green hydrogen technologies. Drawing on international and national policy frameworks, the study identifies financial incentives, regulatory mechanisms, and stakeholder engagement approaches that can foster a circular hydrogen economy. The findings emphasise the need for coordinated governance and robust regulatory instruments to ensure that green hydrogen contributes to both energy security and environmental sustainability. The paper concludes with recommendations for policymakers, industry leaders, and researchers on advancing the circularity of green hydrogen technologies.