English as a Foreign Language (EFL) teachers are always seen as the ones who are responsible for providing effective teaching. In order to do so, it is a must for EFL teachers to have the characteristics of effective EFL teachers. This research points out three of the characteristics of effective EFL teachers namely pedagogical knowledge, personal knowledge, and interpersonal knowledge. The aims of this research are to know English university teachers’ perception the characters of pedagogical knowledge, personal knowledge, and interpersonal knowledge and the contribution of those characteristics into their professional life as effective EFL teachers.This study was conducted at English Education Department, in an Islamic private universityin Yogyakarta, involving three English university teachers. The data of this study were elaborated using qualitative research method, and descriptive qualitative research design. Interview was used as the instrument of this research. The findings showed that pedagogical knowledge as perceived by these participants were the knowledge on how to teach, understand students, and assess students. Their personal knowledge manifested to the way they regargded themselves as teachers and their action as responsible university teachers. The participants also agreed that interpersonal knowledge was the knowledge on how to interact with people, such as students, other university teachers, and also employers. Most of all, the findings showed that those characteristics had appreciable contribution towards their effort in being effective EFL teachers.