ABSTRACT2013 curriculum is the newest curriculum conducted in Indonesia. To measurestudents’ AC in 2013 curriculum, there were many assessments need to beimplemented by the teacher. This research is conducted to explore more about astudy on the implementation of AC in teaching English at SMPN 1 GegerMadiun. The objectives of the research are to explore and describe; 1) the Englishteacher’s attitude towards the implementation of AC; 2) assessments used by theteacher to assess students’ AC; 3) problems the teacher encountered; 4) how theteacher solve the problems; 5) activities that can improve students’ AC; and 6) theeffect of AC to the English achievements. Case study is applied in this research.The respondents of this research are an English teacher from SMP N 1 GegerMadiun and the VII grade students. The respondents are chosen through purposivesampling. The events are the teaching and learning processes. The documentsanalyzed are the syllabus and the lesson plan of English subject of 2013curriculum, the teachers’ profile, students’ attitude information, and students’English achievements. The techniques of collecting the data are observation,interview, questionnaire, and documentation. To analyze the data, the InteractiveModel proposed by Miles and Hubermen was used.The findings demonstrate that: (1) The teacher has a positive attitude towards theimplementation of AC; (2) The teacher implemented 3 kinds of assessments, thosewere observation, journals, and peer evaluation; (3) The problems in theobservation were limited time and teacher’s subjectivity. The problem in journalwas also limited time, while in peer evaluation, the problem is students’subjectivity; (4) The solutions for the problems in observation; the teacherassessed the students’ AC outside classroom, in journal; the teacher also assessesstudents’ AC outside classroom and records the information from the otherteachers, in peer evaluation; the teacher conducted peer evaluation more than onceper semester; (5) to enhance the students’ AC, the school provided intra-curricularand extracurricular activities. While in teaching and learning process, the teacherprovided various kinds of learning approach and methods, reminded and correctedstudents’ attitude, gave advices and motivation, and integrated AC and thematerials, (6) the students’ AC significantly affect the students’ Englishachievement.Keywords: 2013 curriculum, attitude competence, assessments, case study.