Latar Belakang: Infeksi virus Covid-19 masih terus terjadi di berbagai negara, tidak terkecuali Indonesia. Berdasarkan laporan Satgas covid-19, DKI Jakarta merupakan provinsi yang kasus terkonfirmasi positif terbanyak yaitu 411.495 kasus. Semua lapisan masyarakat perlu secara disiplin mematuhi protokol kesehatan, tidak terkecuali pengunjung pasar. Berdasarkan hasil observasi, pengunjung di pasar kebayoran kurang patuh dalam menggunakan masker. Salah satu upaya pencegahan yang direkomendasikan WHO untuk mencegah penyebaran Covid-19 adalah pemakaian masker. Tujuan penelitian dilakukan untuk mengetahui perilaku masyarakat terkait penggunaan masker sebagai upaya pencegahan penyebaran Covid-19. Metode: Studi kualitatif ini dilakukan pada bulan Juli 2021 menggunakan teknik wawancara mendalam pada 7 informan yaitu pedagang, pembeli, dan tukang ojek di pasar Kebayoran, Jakarta Selatan. Instrumen yang digunakan yaitu pedoman wawancara, alat tulis, dan handphone untuk merekam. Validasi menggunakan triangulasi sumber. Hasil: Hasil penelitian ini menunjukan sebagian besar informan masih kurang disiplin menerapkan protokol kesehatan khusunya penggunaan masker. Perilaku informan ini dipengaruhi oleh pengetahuan, kebiasaan tidak menggunakan masker, serta rasa aman dari bahaya Covid-19. Community Behavior Mask of Mask Usage in Prevention Efforts of Covid-19 Transmission in Kebayoran Market of South Jakarta Abstract Background: The Covid-19 virus continues to spread in numerous nations, including Indonesia. According to the report of the Covid-19 Task Force, DKI Jakarta is the province with the highest number of verified positive cases, 411,495 instances. Visitors to the market must adhere to health rules with the same rigour as the rest of society. Observations indicate that visitors to the Kebayoran market are less compliant with mask usage. The World Health Organization recommends the use of masks to avoid the transmission of Covid-19. The objective of the study was to investigate the community's behavior towards the wearing of masks to prevent the transmission of Covid-19. Methods: This qualitative study was conducted during June 2021 using in-depth interviews with 7 informants, namely traders, buyers, and motorcycle taxi drivers at the Kebayoran market, South Jakarta. The instruments used were interview guides, stationery, and cellphones for recording. Validation using source triangulation. Results: According to the findings of this study, the majority of informants still lack discipline in adopting health regulations, particularly the use of masks. This informant's behavior is influenced by his knowledge, his practice of not wearing masks, and his perception of Covid-19's hazards.