This research is conducted to answer the following questions (1) How is the implementation of character building through language teaching at MTs Raudlatul Ulum Guyangan? (2) How is the evaluation of character building through English language teaching at MTs Raudlatul Ulum Guyangan? (3) What are the factors inhibit and support character building through language teaching at MTs Raudlatul Ulum Guyangan?
This research uses qualitative research. The data were collected through three techniques: interview, observation, and documentation. Raudlatul Ulum differentiate between male students and female student in different time of school. Male students follow teaching learning process at 06.45 until 12.30, whereas female students follow teaching learning process on 13.00 until 17.00. This research focused on eight grade female students of MTs Raudlatul Ulum Guyangan because a reason that the researcher is female, and female has no permission to conducts research on male class.
The result of this research are; implementation of character building through language teaching the uses material of the book (English on Sky), there are some stories about public figures, and the teacher slip the points of characters, for example the figures’ honesty, religioun, discipline, confidence, creativity, independence, curiousity, communication, environmental care, social care, and responsibility. The evaluation of character building are through teachers’ observation of students’ behavior at class, self assessment of students, and journal assessment. The supporting factor on character building through language teaching is from Raudlatul Ulum foundation itself that emphasize character building, whereas inhibiting factor is the students’ interest in some other subjects, not in English.