Fragmentation of ancestral land (pusako tinggi) in West Sumatra is increasing along with population growth, with Generation Z (Gen Z) as the dominant demographic group. This phenomenon has the potential to threaten the sustainability of the customary inheritance tradition if Gen Z, as the recipient of the inheritance, does not understand the tradition of inheriting pusako tinggi land comprehensively. This qualitative study examines the knowledge of Gen Z Nagari Lawang about the inheritance of ancestral land of pusako tinggi. Purposive sampling was used to identify informants through in-depth interviews, participant observation, and document studies. This study found that Gen Z Nagari Lawang is less aware of (1) the method of inheritance when there is a pupus (extinction of the lineage), (2) the role of gender in the management of ancestral land of pusako tinggi, and (3) its philosophical function. The mobility of Gen Z to study abroad and the practice of relaxed use of ancestral land of pusako tinggi from the mother's family are the causes. This study found that learning of customs occurs informally through daily observations so that there are variations in interpretation between families. To overcome this, this research recommends (1) revitalization of the intrinsic values of inherited customs, (2) formation of indigenous youth communities, (3) codification of customary rules in writing, and (4) tripartite synergy between the community, Village Head, and Nagari Customary Council (KAN) in the socialization and implementation of customary rules. Fragmentasi tanah leluhur (pusako tinggi) di Sumatera Barat semakin meningkat seiring dengan pertumbuhan penduduk, dengan Generasi Z (Gen Z) sebagai kelompok demografi yang dominan. Fenomena ini berpotensi mengancam keberlanjutan tradisi pewarisan adat apabila Gen Z sebagai penerima warisan tidak memahami tradisi pewarisan tanah pusako tinggi secara komprehensif. Penelitian kualitatif ini mengkaji pengetahuan Gen Z Nagari Lawang tentang pewarisan tanah leluhur pusako tinggi. Pengambilan sampel secara purposive digunakan untuk mengidentifikasi informan melalui wawancara mendalam, observasi partisipatif, dan studi dokumen. Penelitian ini menemukan bahwa Gen Z Nagari Lawang kurang menyadari (1) cara pewarisan ketika terjadi pupus (punahnya garis keturunan), (2) peran gender dalam pengelolaan tanah leluhur pusako tinggi, dan (3) fungsi filosofisnya. Mobilitas Gen Z untuk sekolah di luar negeri dan praktik kelonggaran pemanfaatan tanah leluhur pusako tinggi dari keluarga ibu menjadi penyebabnya. Penelitian ini menemukan bahwa pembelajaran adat istiadat terjadi secara informal melalui pengamatan sehari-hari sehingga terjadi variasi penafsiran antar keluarga. Untuk mengatasi hal tersebut penelitian ini menyarankan (1) revitalisasi nilai-nilai hakiki adat istiadat yang diwariskan, (2) pembentukan komunitas pemuda adat, (3) kodifikasi aturan adat secara tertulis, dan (4) sinergi tripartit antara masyarakat, Kepala Desa, dan Dewan Adat Nagari (KAN) dalam sosialisasi dan implementasi aturan adat.