Purpose: The use of social media for sustainable information is important since it has the potential to influence people's intentions and behaviour towards sustainability. As previous studies on social media and sustainable development have primarily focussed on Western viewpoints, this study presents a comprehensive Asian perspective by investigating the impact of social media on sustainable intention and behaviour amongst Malaysian and Indonesian undergraduate university students. Design/methodology/approach: A campus-wide online survey was conducted with 953 students from Malaysia and Indonesia. The researchers collected data through an online questionnaire and a two-week quantitative survey of undergraduate students in Malaysia and Indonesia. Quantitative data were analysed by SmartPLS software and comparative studies were conducted. Findings: The result of the survey indicated that Facebook and Instagram were mainly used by Malaysian students to obtain and communicate about sustainability information, whilst Instagram was mainly used by Indonesian students. The findings also discovered that social media usage and social media effectiveness and usefulness are statistically significant predictors of sustainable intention amongst the students in Malaysia and Indonesia. Sustainable intention is also a statistically significant predictor of sustainable behaviour amongst the students. Additionally, this study also found that Malaysian students appeared to have a high level of the effect of sustainable intention on sustainable behaviour and the effect of the effectiveness and usefulness of social media to sustainable intention compared to Indonesian students. On the contrary, their use of social media related to sustainable behaviour was relatively low compared to Indonesian students. Originality/value: Overall, the findings can contribute to the presently scant empirical works that focus on social media's influence on sustainability and sustainable development. Furthermore, the findings contribute to the growing body of knowledge related to sustainability communication and sustainable education, particularly in terms of the use of social media in the learning and teaching process. Future research could focus on studying postgraduate students and university students from other Asian countries. Moreover, using qualitative methods like in-depth interviews or focus group discussion and applying other theories might unveil further results.