ABSTRAK Penelitian ini berjudul “Pelaksanaan Perjanjian Jual Beli Kain Tenun Songket antara Pengrajin dengan Pembeli Secara Pre-Order di Dusun Semberang Desa Sumber Harapan Kabupaten Sambas”. Penelitian ini dilatarbelakangi oleh praktik jual beli kain tenun songket yang dilakukan melalui sistem pre-order, di mana barang belum tersedia pada saat perjanjian dibuat dan proses produksi membutuhkan waktu cukup lama. Dalam praktiknya, perjanjian antara pengrajin dan pembeli umumnya dilakukan secara lisan dengan mengandalkan asas kepercayaan dan itikad baik. Kondisi tersebut menimbulkan permasalahan hukum, terutama ketika terjadi wanprestasi dari pihak pembeli, seperti pembatalan sepihak, keterlambatan pembayaran, atau tidak melakukan pelunasan setelah kain selesai diproduksi, yang pada akhirnya merugikan pengrajin. Rumusan masalah dalam penelitian ini adalah apakah pelaksanaan perjanjian jual beli kain tenun songket secara pre-order antara pengrajin dan pembeli di Kabupaten Sambas telah dilaksanakan sesuai dengan kesepakatan para pihak. Penelitian ini bertujuan untuk mengetahui pelaksanaan perjanjian tersebut, faktor penyebab terjadinya wanprestasi oleh pembeli, akibat hukum yang timbul, serta upaya yang dilakukan pengrajin dalam menyikapi wanprestasi. Metode penelitian yang digunakan adalah penelitian hukum empiris dengan pendekatan sosiologis, melalui pengumpulan data lapangan dan analisis terhadap ketentuan hukum perdata, khususnya KUH Perdata mengenai perjanjian dan wanprestasi. Hasil penelitian menunjukkan bahwa pelaksanaan perjanjian jual beli kain tenun songket secara pre-order di Kabupaten Sambas belum sepenuhnya dilaksanakan sesuai dengan kesepakatan para pihak. Hal ini disebabkan oleh masih dominannya perjanjian lisan tanpa pengaturan tertulis mengenai hak, kewajiban, serta sanksi, sehingga membuka peluang terjadinya wanprestasi oleh pembeli. Faktor penyebab wanprestasi antara lain alasan ekonomi pembeli, perubahan keinginan, serta kurangnya pemahaman terhadap konsekuensi hukum perjanjian. Akibat hukum dari wanprestasi tersebut pada dasarnya memberi hak kepada pengrajin untuk menuntut pemenuhan perjanjian atau ganti kerugian, namun dalam praktiknya penyelesaian lebih banyak dilakukan secara kekeluargaan atau musyawarah. Penelitian ini menyarankan pentingnya penerapan perjanjian tertulis serta kejelasan pengaturan pembayaran dan sanksi guna memberikan kepastian dan perlindungan hukum bagi pengrajin maupun pembeli. Kata kunci: Perjanjian jual beli, pre-order, kain tenun songket, wanprestasi ABSTRACT This study is entitled “The Implementation of Pre-Order Sale and Purchase Agreements of Songket Woven Fabric between Artisans and Buyers in Semberang Hamlet, Sumber Harapan Village Sambas Regency.” This research is motivated by the practice of buying and selling songket woven fabric through a pre-order system, in which the goods are not yet available at the time the agreement is made and the production process requires a considerable amount of time. In practice, agreements between artisans and buyers are generally conducted orally, relying on the principles of trust and good faith. This condition gives rise to legal issues, particularly when a breach of contract occurs on the part of the buyer, such as unilateral cancellation, late payment, or failure to complete payment after the fabric has been produced, which ultimately causes losses to the artisans. The problem formulation in this study is whether the implementation of the pre-order sale and purchase agreement of songket woven fabric between artisans and buyers in Sambas Regency has been carried out in accordance with the agreement of the parties. This research aims to examine the implementation of the agreement, the factors causing breach of contract by buyers, the resulting legal consequences, and the efforts made by artisans in responding to such breaches. The research method used is empirical legal research with a sociological approach, through field data collection and analysis of civil law provisions, particularly the Indonesian Civil Code concerning agreements and breach of contract. The results show that the implementation of pre-order sale and purchase agreements of songket woven fabric in Sambas Regency has not been fully carried out in accordance with the agreement of the parties. This is due to the predominance of oral agreements without written arrangements regarding rights, obligations, and sanctions, thereby creating opportunities for breach of contract by buyers. Factors causing breach of contract include the buyer’s economic reasons, changes in preferences, and lack of understanding of the legal consequences of agreements. The legal consequences of such breaches essentially grant artisans the right to demand fulfillment of the agreement or compensation for losses; however, in practice, dispute resolution is more often conducted through family-based deliberation or amicable settlement. This study suggests the importance of implementing written agreements and clear arrangements regarding payment and sanctions in order to provide legal certainty and protection for both artisans and buyers. Keywords: Sale and purchase agreement, pre-order, songket woven fabric, breach of contract.