Abstrak: Tujuan penelitian ini adalah untuk mengetahui kemampuan penalaran deduktif matematis siswa dalam menyelesaikan soal matematika bentuk cerita pokok bahasan aplikasi turunan. Penelitian ini dilakukan di SMA Muhammadiyah  02 Cipondoh Tangerang. Pengumpulan data dilakukan dengan metode observasi, wawancara, tes dan studi dokumentasi. Teknik analisis data menggunakan analisis data kualitatif yang meliputi reduksi data, penyajian data dan menarik kesimpulan/verifikasi. Berdasarkan hasil penelitian diperoleh siswa dengan kemampuan penalaran deduktif tinggi mencapai 12,82%, siswa dengan kemampuan penalaran deduktif sedang mencapai 71,8% dan siswa dengan kemampuan penalaran deduktif rendah mencapai 15,38%.Abstract:  The purpose of this research is to know the mathematical deductive reasoning ability of students in solving math story form the subject of derivative applications. This research was conducted in High School of Muhammadiyah 02 Cipondoh Tangerang. Data collection is done by the method of observation, interview, test and study of documentation. Data analysis techniques used qualitative data analysis that included the reduction of the data, the presentation of the data and draw conclusion/verification. Based on the research results obtained by students with high ability of deductive reasoning reached 12.82%, students with middle ability of deductive reasoning reached 71.8% and students with low ability deductive reasoning reached 15.38%.