Abstrak: Penelitian ini bertujuan mendeskripsikan hambatan guru matematika SMP dalam mengimplementasikan Kurikulum 2013. Penelitian ini merupakan penelitian deskriptif eksploratif dengan pendekatan kualitatif. Data dikumpulkan dengan teknik wawancara dan focus group discussion. Sumber data adalah 10 guru mata pelajaran matematika SMP di Provinsi Daerah Istimewa Yogyakarta. Analisis data dilakukan dengan mencari tema, kemudian menentukan hubungan antartema untuk memeroleh pemahaman. Hasil penelitian sebagai berikut. Pertama, pelatihan dan sosialisasi belum dapat memberikan pemahaman yang baik dan menyeluruh mengenai Kurikulum 2013. Kedua, guru kesulitan mengatur waktu pada perencanaan pembelajaran, merencanakan pembelajaran, merencanakan penilaian sikap, dan memilah pengetahuan dan keterampilan pada penyusunan instrumen penilaian. Ketiga, keterbatasan waktu dalam pelaksanaan pembelajaran, kesulitan berkaitan dengan perangkat pembelajaran, dan kesulitan mengaktifkan siswa. Keempat, sistem penilaian yang rumit dan perlu waktu yang lama untuk menyusun laporan. Kata Kunci: hambatan guru matematika SMP, implementasi kurikulum baru THE OBSTACLES OF JUNIOR HIGH SCHOOL MATHEMATICS TEACHERS IN IMPLEMENTING THE NEW CURRICULUM Abstract: The study was to describe the obstacles of junior high school mathematics teachers in implementing the new curriculum, namely Curriculum 2013, in most of junior high schools in Indonesia. The study was a descriptive explorative research by means of qualitative approach. The data were gathered by means of interviews and focus group discussions. The data source was 10 junior high school mathematics teachers in the Province of Yogyakarta Special Region, Indonesia. The data were analyzed by looking for the themes and finding the relationship among the themes in order to gain the proper understanding. The results of the study showed that the obstacles that the teachers were as follows. First, the socialization and training programs had not been able to provide good and through understanding of the new curriculum. Second, the teachers had difficulties in arranging the time for the lesson plan, the teaching plan, the attitude assessment plan and the categorization between the knowledge and the skills in the composition of assessment instrument. Third, the implementation of the lesson plan had limited time in addition to the difficulties in designing the teaching kits and in activating the students. Forth, the assessment system was intricated and time consuming especially in the reporting process. Keywords: obstacles of junior high school mathematics teachers, implementing new curriculum