Tujuan penelitian ini adalah untuk mendeskripsikan kemampuan berpikir kritis berbasis gaya kognitif impulsif dan reflektif. Metode penelitian menggunakan pendekatan kualitatif deskriptif. Data diambil dengan tes kemampuan berpikir kritis matematika, Matching Familiar Figure Test (MFFT) untuk mengukur gaya kognitif, dan wawancara. Hasil tes siswa dianalisis, kemudian dipilih empat siswa, dua gaya kognitif impulsif, dan gaya kognitif reflektif, untuk analisis kualitatif. Hasil penelitian menunjukkan bahwa kemampuan berpikir kritis matematika siswa dengan gaya kognitif reflektif lebih baik daripada siswa dengan gaya kognitif impulsif pada indikator pemahaman masalah, memberikan alasan logis dengan berbagai konsep yang relevan dan menghubungkan antar konsep, serta membuat kesimpulan. Sedangkan pada indikator pemecahan masalah konsep, siswa dengan gaya kognitif impulsif lebih baik daripada siswa dengan gaya kognitif reflektif.The purpose of this research was to describe the critical thinking ability of based on impulsive and reflective cognitive style. The research method used a descriptive qualitative approach. Data was taken with the ability of mathematics critical thinking test, Matching Familiar Figure Test (MFFT) to measure cognitive style, and interview. The student’s test result was analysed, then four students were selected, the two of them are impulsive cognitive style, and the others are reflective cognitive style, for qualitative analysis. The result showed that the ability of mathematics critical thinking students with reflective cognitive style is better than students with impulsive cognitive style on the indicators of understanding the problem, giving logical reasons with various relevant concepts and connecting between concepts, and making conclusions. While on the indicator of solving problems with the concepts, students with impulsive cognitive style is a better than students with reflective cognitive style.