JUAL BELI BLIND BOX DALAM PERSPEKTIF HUKUM PERDATA DAN HUKUM ISLAMNIM.: 22103060015Farihah Fadhrah Ilahi HermawanauthorBuying and selling blind boxes is a modern transaction model in which products are sold in sealed packaging without the consumer knowing the contents. This practice offers the thrill of surprise and uncertainty as its main appeal; the buyer does not know the specific item being sold at the time the transaction is concluded. Under such circumstances, fairness cannot be ensured. However, this practice raises legal issues because the buyer does not know the specific subject matter of the transaction at the time the contract is entered into. This lack of clarity regarding the subject matter has the potential to conflict with the requirements for a valid contract under civil law as well as the requirements for the validity of a contract under Islamic law; therefore, it requires in-depth analysis to provide legal certainty for the parties involved. This study employs a normative legal methodology with a statutory, conceptual, and comparative approach through library research on primary and secondary legal sources. Data analysis was conducted in three stages: description of legal norms, comparison between the two legal systems, and drawing of conclusions. This approach was chosen because it allows for a systematic analysis of civil law provisions specifically Article 1320 of the Civil Code as well as the principles of contract validity in Islamic law. Thus, this study not only compares two legal systems but also identifies common ground for assessing the validity of blind box transactions. The results of the study show that: First, under civil law, the legal status of blind box sales is conditional and depends on the level of transparency of information provided by the seller to the buyer. If the seller honestly lists the variants along with the percentages of their appearance (odds disclosure), the agreement is formally valid under Article 1320 in conjunction with Article 1333 of the Civil Code. Conversely, if information is concealed or misleading, the transaction violates the principle of good faith under Article 1338(3) of the Civil Code and may be classified as a tort under Article 1365 of the Civil Code. Meanwhile, according to Islamic law, the status of blind box sales is also conditional; they are permissible (mubah) if conducted through a conditional contract (al-'aqd al-mu'allaq) that includes a full obligation to disclose the odds, based on the principle of freedom of contract, as reinforced by the hadith “almuslimūna ‘alā syurūṭihim” and the principle of permissibility (ibahah) in Sharia contract law. Second, the implications of blind box sales under these two legal systems are the need for more specific technical regulations in the form of enforceable odds disclosure requirements, as well as a special fatwa from the MUI/DSN that sets forth concrete operational standards for Muslim businesses.340.2 Hukum Perbandingan2026-06-25UIN SUNAN KALIJAGA YOGYAKARTA;FAKULTAS SYARI’AH DAN HUKUMThesis