Global student mobility has reached far beyond Europe, North America, and Australia. Malaysia, Singapore, and South Korea have become the 'emerging contenders' focusing on attracting international students, primarily from other Asian countries. This heightened competition among higher education institutions (HEIs) challenges their sustainability. This study, therefore, aims to investigate Alcaide-Pulido, Alves, and Gutiérrez-Villar's university image model and its influence on students' citizenship behaviour in the context of HEIs' achieving sustainability. Data were collected from 223 international students at two reputable Malaysian universities. The results, showing that 'image' is a 'higher-order construct', extend the university image model and reveal a reformation of the 'image' variables. The findings further reveal that the extended and reformed model is capable of building satisfaction among students, which, in turn, contributes to enhancing students' citizenship behavioural outcomes (advocacy, feedback, helping behaviour, and tolerance). This can indirectly support HEIs' sustainability.