<![CDATA[This study aims to analyze the transformational leadership strategies employed by a madrasah principal to optimize the Check and Act phases of the Plan–Do–Check–Act (PDCA) cycle for improving instructional quality at MIS Nahdlatul Wathan Keruak. A qualitative case study design was employed. Informants were purposively selected, consisting of the principal, three teachers, three students, one administrative staff member, and one parent representative. Data were collected through in-depth interviews, focus group discussions, non-participant observations, and documentation analysis, subsequently examined using interactive qualitative data analysis supported by NVivo 15 software. The findings reveal that transformational leadership successfully optimized the Check phase through dialogue-based clinical supervision, structured evaluations, constructive feedback, and collaborative reflective inquiries. Meanwhile, the Act phase was operationalized through the standardization of best teaching practices, continuous teacher professional development, instructional design refinements, and institutional quality governance strengthening. The coherent implementation of these two phases was reinforced by shared organizational commitment and community trust, contributing positively to enhanced pedagogical competencies, active student learning engagements, and a sustainable institutional quality culture. ABSTRAK Penelitian ini bertujuan menganalisis strategi kepemimpinan transformatif kepala madrasah dalam mengoptimalkan tahap Check dan Act pada siklus Plan–Do–Check–Act (PDCA) untuk meningkatkan mutu pembelajaran di MIS Nahdlatul Wathan Keruak. Penelitian menggunakan pendekatan kualitatif dengan desain studi kasus. Informan terdiri atas kepala madrasah, tiga guru, tiga siswa, satu staf tata usaha, dan satu perwakilan wali murid yang dipilih secara purposif. Pengumpulan data dilakukan melalui wawancara mendalam, focus group discussion, observasi nonpartisipatif, dan analisis dokumentasi yang dianalisis secara interaktif menggunakan perangkat lunak NVivo 15. Hasil penelitian menunjukkan bahwa kepemimpinan transformatif mengoptimalkan tahap Check melalui supervisi klinis berbasis dialog, evaluasi berkala, umpan balik konstruktif, serta refleksi kolaboratif. Sementara itu, tahap Act diwujudkan melalui standardisasi praktik baik, program pengembangan kompetensi pendidik, modifikasi desain instruksional, serta pelembagaan sistem penjaminan mutu internal. Implementasi kedua tahapan tersebut ditopang oleh komitmen bersama warga madrasah dan partisipasi masyarakat, sehingga berkontribusi nyata terhadap peningkatan profesionalisme guru, keterlibatan aktif siswa, dan iklim mutu madrasah. ]]>
