Abstrak: Penelitian ini bertujuan untuk mengetahui bagaimana self-efficacy santri setelah menggunakan modul pembelajaran berbasis pesantren dengan pendekatan saintifik. Metode penelitian yang digunakan dalam penelitian ini adalah penelitian kuantitaif dengan menggunakan pendekatan pre experimental design. Pendekatan pre experimental design yang digunakan dalam penelitian ini menggunakan jenis one group pretest-posttest study. Hasil analisis angket self-efficacy menunjukkan bahwa terdapat peningkatan self-efficacy santri antara sebelum dan sesudah menggunakan modul. Hasil analisis sumber self-efficacy setelah menggunakan modul diperoleh bahwa sumber mastery experience dan social persuasions berada pada kategori tinggi, sumber vicarious experience berada pada kategori sangat tinggi, sedangkan sumber physiological state berada pada kategori sedang. Hasil analisis skor seluruh angket menunjukkan self-efficacy santri berada pada kategori tinggi setelah pemakaian modul. Abstract: The goal of this research is to assess students' self-efficacy after utilizing Islamic boarding school-based mathematics learning module with scientific approach. The research method used in this research using a pre experimental design approach.The pre experimental design approach used in this study used the type of one group pretest-posttest study. The examination of the self-efficacy questionnaire revealed that students' self-efficacy increased between before and after using the module. After using the module, the sources of mastery experience and social persuasion were in the high category, sources of vicarious experience were in the very high category, and sources of physiological state were in the medium category, according to the results of the self-efficacy sources analysis. After using the module, the students' self-efficacy was in the high category, according to the results of the analysis of all the questionnaire scores.