Abstrak: Penelitian ini bertujuan untuk mengetahui (1) eksistensi MGMP Geografi tingkat SMA (2) partisipasi MGMP Geografi tingkat SMA dalam penyusunan bahan ajar, dan (3) peran MGMP Geografi tingkat SMA dalam meningkatkan profesionalisme guru terhadap penyusunan bahan ajar. Penelitian ini dilakukan di Kota Medan dan Kabupaten Deli Serdang Provinsi Sumatera Utara. Teknik analisis data yang digunakan yaitu deskriptif kualitatif. Penentuan subjek penelitian menggunakan random sampling dengan jumlah sampel sebanyak 30 orang. Teknik pengumpulan data yang digunakan pada penelitian ini adalah observasi ke lapangan, wawancara, angket dan studi dokumentasi. Hasil penelitian menunjukkan bahwa (1) eksistensi MGMP saat ini termasuk kategori kurang baik dengan persentase 53,31% pada Kota medan dan 46,68% pada Kabupaten Deli Serdang (2) Partisipasi MGMP termasuk dalam kategori kurang baik dengan persentase 46,67% pada Kota Medan dan 53,34% pada Kabupaten Deli Serdang (3) Peran MGMP Geografi dalam meningkatkan profesionalisme guru terhadap penyusunan bahan ajar termasuk kedalam kategori kurang baik dengan persentase di 50% pada Kota Medan dan 50% pada Kabupaten Deli Serdang. Abstract: This study aims to determine (1) the existence of a high-level Geography MGMP (2) the participation of a high-level Geography MGMP in the preparation of teaching materials, and (3) the role of a high-level Geography MGMP in improving teacher professionalism in the preparation of teaching materials. This research was conducted in Medan City and Deli Serdang Regency, North Sumatra Province. The data analysis technique used is descriptive qualitative. The population in this study were all teachers who are members of MGMP Medan City and Deli Serdang Regency. Determination of the sample using random sampling with a total sample of 30 people. Data collection techniques used in this study were field observations, interviews, questionnaires and documentation studies. The results showed that (1) the existence of high school level MGMP in Medan City and Deli Serdang Regency is currently classified as inadequate with a percentage of 53.31% in Medan City and 46.68% in Deli Serdang Regency (2) MGMP participation is included in unfavorable category with a percentage of 46.67% in Medan City and 53.34% in Deli Serdang Regency (3) Role of Geography MGMP in improving teacher professionalism in the preparation of teaching materials is included in the category of unfavorable with a percentage at 50% in Medan City and 50 % in Deli Serdang Regency
