This study aims at improving teacher professionalism. This study employed descriptive qualitative case study using supervision instrument. The data were obtained through observation, interview, and documentation. The data were analyzed through several steps such as obtaining data, reducing data, presenting data, and drawing a conclusion. The result of this study showed that the implementation of clinical supervision which is conducted in three stages (planning, execution, and feedback responding) was positively running and able to improve the professionalism of teacher. Several attempts to improve and develop teacher professionalism were made such as material comprehension, learning method and media used designation. Penelitian ini bertujuan untuk meningkatkan profesionalisme guru. Metode yang digunakan kualitatif deskriptif dengan rancangan penelitian studi kasus menggunakan instrumen supervisi. Pengumpulan data menggunakan observasi, wawancara, dan studi dokumentasi. Teknik analisis data meliputi pengumpulan data, reduksi data, penyajian data, dan penarikan kesimpulan. Hasil penelitian menunjukkan implementasi supervisi klinis yang dilaksanakan dalam tiga tahap yaitu tahap perencanaan, tahap pelaksanaan, dan tahap umpan balik telah berjalan dengan baik dan dapat meningkatkan profesionalisme guru. Berbagai upaya peningkatan dan pengembangan profesional guru telah diusahakan, seperti penguasaan materi, pemilihan metode pembelajaran, dan media yang digunakan.