Planetary health is an emerging field that highlights the strong connection between human health and the environment. With increasing challenges such as climate change, urbanisation, biodiversity loss, and pollution, there is a growing need for research, innovation, and collaboration to protect both people and the planet. The Regional Postgraduate Symposium on Planetary Health 2026 aims to provide a platform for postgraduate students across Southeast Asia to share research, exchange ideas, and build meaningful collaborations. By bringing together young researchers and partnering institutions such as Universiti Teknologi Brunei, Universiti Brunei Darussalam, University of the Philippines Diliman and Sunway Centre of Planetary Health, the symposium encourages interdisciplinary approaches and strengthens regional research capacity.