This study aims to describe and analyze the application of the Tahrir al-Aqwal memorization method to improve the understanding of grammar among first-grade female students at the Muslimat Samalanga Islamic Boarding School in Bireuen Regency, Aceh Province. Tahrir al-Aqwal is a classical text used in basic grammar instruction, particularly regarding the factors (awâmil) that influence word endings in Arabic. The memorization method was chosen because it is considered effective in developing a strong grammatical framework and deeply embedding the rules in the students' minds. This study employed a qualitative approach with descriptive methods. Data were collected through observation, in-depth interviews, and documentation. The key informants were the teaching staff, first-grade female students, and the Islamic boarding school principal. Data analysis employed the Miles and Huberman interactive model, which encompasses data reduction, data presentation, and conclusion drawing. Data validity was strengthened by triangulation of sources and techniques. The results of this study indicate that the memorization method of the Tahrir al-Aqwal book not only helps female students memorize the rules of grammar but also improves their understanding of Arabic sentence structure in a practical way. The memorization activity is carried out in stages, accompanied by sima'an (recitation), explanations of meaning, and sentence analysis exercises. This process fosters discipline, perseverance, and logical thinking skills in the female students. Despite challenges in maintaining consistency and understanding, the teacher's contextual approach overcomes these obstacles. Thus, the memorization method of classical books remains relevant as an effective strategy for teaching the science of tools in Islamic boarding schools. Penelitian ini bertujuan untuk mendeskripsikan dan menganalisis penerapan metode hafalan kitab Tahrîr al-Aqwâl dalam meningkatkan pemahaman ilmu nahwu pada santriwati kelas I di Dayah Putri Muslimat Samalanga, Kabupaten Bireuen, Provinsi Aceh. Kitab Tahrîr al-Aqwâl merupakan salah satu teks klasik yang digunakan dalam pembelajaran dasar ilmu nahwu, khususnya mengenai faktor-faktor (‘awâmil) yang memengaruhi perubahan akhir kata dalam bahasa Arab. Metode hafalan dipilih karena dianggap efektif dalam membentuk kerangka berpikir gramatikal yang kuat serta menanamkan kaidah secara mendalam dalam ingatan santri. Penelitian ini menggunakan pendekatan kualitatif dengan metode deskriptif. Data dikumpulkan melalui observasi, wawancara mendalam, dan dokumentasi, dengan informan utama terdiri dari guru pengampu, santriwati kelas I, dan pimpinan dayah. Teknik analisis data menggunakan model interaktif Miles dan Huberman, yang meliputi reduksi data, penyajian data, dan penarikan kesimpulan. Keabsahan data diperkuat dengan triangulasi sumber dan teknik. Hasil penelitian menunjukkan bahwa metode hafalan kitab Tahrîr al-Aqwâl tidak hanya membantu santriwati dalam mengingat kaidah-kaidah nahwu, tetapi juga meningkatkan pemahaman mereka terhadap struktur kalimat bahasa Arab secara aplikatif. Kegiatan hafalan dilakukan secara bertahap, disertai dengan sima’an, penjelasan makna, dan latihan analisis kalimat. Proses ini membentuk kedisiplinan, ketekunan, dan kemampuan berpikir logis santriwati. Meskipun terdapat tantangan dalam menjaga konsistensi dan pemahaman, pendekatan kontekstual dari guru mampu mengatasi kendala tersebut. Dengan demikian, metode hafalan kitab klasik tetap relevan sebagai strategi efektif dalam pembelajaran ilmu alat di pesantren.