Environmental sustainability is a major concern of contemporary societies, businesses, and governments. However, there is a lack of knowledge as to how countries can achieve the goal to end poverty, whilst protecting the planet. It is the objective of our study to examine the moderating role of institutional quality on the financial development and environmental quality nexus in South Asia. Our sample consists of panel data of five South Asian countries (India, Bangladesh, Nepal, Sri Lanka and Pakistan) from 1984 to 2018. We find that financial development increases CO2 emissions in this region, implying that countries in South Asia have utilized financial development for capitalization, instead of improving production technology. Institutional quality moderates the negative impact of financial development on environmental sustainability. An implication of our findings is that efforts to improve institutional quality may help to promote sustainable development in South Asia.