This paper analyzes the interpersonal metafunction in text messages of teachers of English at Viet Anh School. The paper uses Systemic Functional Grammar as the theoretical framework which aims to investigate into a language from a qualitative approach. The aim of this paper is to discover how interpersonal metafunction is being served in text messages of teachers of English in terms of mood, speech function, modality and personal pronouns. The analysis indicates that the English teachers often use text messages for providing more information and demanding services by the dominant use of declaratives clauses in their interaction. These English teachers also perform their plans or desires about their future intention through the frequent use of modality such as ‘will’, ‘can’ or ‘could’. Through the analysis of personal pronouns, it can be clear that the English teachers tend to interact with each other by sharing their points of view rather than mentioning about other things or persons. Their social relation is shorten through the popular use of pronouns ‘I’, ‘we’ and ‘you’. Thus, it can be concluded that the social relationship among the English teachers is established and maintained through the use of interpersonal metafunction.