The students of Pondok Modern Gontor are obligated to speak Gontor formal language because it is the rule for all students. In fact, the students rarely speak formally but too often they speak by Indonesian Language or other languages than the language obliged by Gontor. The large number of offences carried out students’ language to the decline of the quality of Gontor formal language among students. This research is for knowing an academic supervisor interpersonal communication with his students in disciplining Gontor formal language. Qualitative method is used in this research. Collecting data is done by observation and interview with the class 5R academic supervisor, a language advisory council staff, and the chief of class 5R in Pondok Modern Darussalam Gontor. Based on research result that the class 5R academic supervisor interpersonal communication with the students in disciplining Gontor formal language is done by five indicators of interpersonal communication. They are the openness, empathy, a supporting attitude, a positive attitude and equality. This research contributes in disciplining Gontor formal language to improve the quality of students in speaking formally and making them easier to understand the lesson which is used Arabic and English. The intense interpersonal communication The intense interpersonal communication in disciplining Gontor formal language is happened because the close interpersonal connection between the academy supervisor and the students. It is happened because the academic supervisor as parent, as cleric (syaykh), as ustadz, as leader, as manager, as brother, and as friend for them. Keyword: Interpersonal Communicatin, Gontor Formal Language, Academic Supervisor, Student.