<![CDATA[Abstract: This study aims to develop a teslet-model test based on Sasak local wisdom in geometry material to improve students’ mathematical literacy skills. The research employed a Research and Development (R&D) approach using the Borg & Gall model, which was modified into seven stages: initial data collection, planning, initial product development, limited trial, product revision, field trial, and final revision. The instrument consisted of 21 items grouped into 7 teslets, integrating Sasak cultural contexts such as traditional architecture, traditional weaving (tenun), and local arts into geometric concepts. Expert validation results showed an Aiken’s V value of 0.68125 (high category), and the instrument’s reliability reached 0.761 (high category). The item difficulty analysis indicated a proportional distribution dominated by medium-level items, while the discrimination index analysis revealed that most items fell into the good or very good categories. Field trials conducted with seventh-grade students at SMP Negeri 1 Selong demonstrated that the instrument obtained an effectiveness score of 380, categorized as moderately effective in improving mathematical literacy. This was reflected in students’ increased understanding of geometric material as well as their appreciation of local cultural values.Thus, the Sasak local-wisdom-based teslet developed in this study is not only valid, reliable, and feasible as an assessment instrument, but also contributes significantly to preserving local culture and strengthening contextual learning in schools. Abstrak: Penelitian ini bertujuan mengembangkan tes model teslet berbasis kearifan lokal Sasak pada materi geometri untuk meningkatkan kemampuan literasi matematika siswa. Metode penelitian yang digunakan adalah Research and Development (R&D) dengan model Borg & Gall yang dimodifikasi menjadi tujuh tahap: pengumpulan data awal, perencanaan, pengembangan produk awal, uji coba terbatas, revisi produk, uji coba lapangan, serta revisi final. Instrumen berupa 21 soal yang terbagi jadi 7 teslet yang memadukan konteks budaya Sasak, seperti arsitektur tradisional, kerajinan tradisional (tenun), dan kesenian tradisional, dengan konsep geometri. Hasil validasi ahli menunjukkan nilai Aiken’s V sebesar 0,68125 (kategori tinggi), sedangkan reliabilitas instrumen mencapai 0,761 (kategori tinggi). Analisis tingkat kesukaran memperlihatkan distribusi soal yang proporsional dengan dominasi kategori sedang, sementara uji daya beda menunjukkan sebagian besar soal tergolong baik dan sangat baik. Uji coba lapangan pada siswa kelas VII SMP Negeri 1 Selong menunjukkan bahwa instrument memiliki skor evektifitas 380 kategori cukup efektif dalam meningkatkan literasi matematika, ditandai dengan peningkatan pemahaman siswa terhadap materi geometri sekaligus apresiasi mereka terhadap nilai budaya lokal. Dengan demikian, teslet berbasis kearifan lokal Sasak yang dikembangkan tidak hanya valid, reliabel, dan layak digunakan sebagai instrumen penilaian, tetapi juga memberikan kontribusi penting dalam pelestarian budaya lokal dan penguatan pembelajaran kontekstual di sekolah.]]>
