Land disputes are a significant legal issue in Indonesia, often arising from various complexities involving land ownership and the legal processes governing it. One of the most common causes of land disputes is the improper issuance of legal documents, such as the Sale and Purchase Deed (Akta Jual Beli or AJB), which may be created without proper authorization or procedure. This situation frequently leads to conflicts, particularly when one party's rights are violated by unlawful acts or negligence during the legal process. This study examines the legal consequences and resolution mechanisms of the issuance of an unlawful AJB, focusing on the Supreme Court Decision Number 3507 K/Pdt/2023. In this research, the primary objective is to analyzing the legal consequences of issuing an AJB that contravenes the requirements of the Indonesian Civil Code, specifically Article 1365, which addresses perbuatan melawan hukum (unlawful acts). By focusing on the statutory provisions outlined in the Civil Code, the study highlights the importance of ensuring that all elements of a valid contract, including mutual consent, capacity, a lawful object, and a legal cause, are fully met. Failure to satisfy these formal and material requirements renders the transaction invalid and can result in legal consequences, including the annulment of the AJB. Furthermore, this study investigates the legal avenues available to resolve disputes arising from unlawful actions related to land transactions. In cases where an AJB has been issued unlawfully, the law provides various methods of remedy, including civil claims for compensation, administrative corrections, and the restoration of property rights. These remedies are essential for ensuring that property ownership is recognized and protected under the law. The study emphasizes the significance of proper legal procedures and the need for all parties involved to act in good faith throughout the process of land transactions. The research adopts a normative legal approach, utilizing statutory interpretation, conceptual analysis, and case studies to explore the application of unlawful act in land disputes. The findings of this study contribute to a deeper understanding of how violations in land transactions undermine legal certainty and the protection of property rights. Additionally, the study underscores the necessity of enforcing legal compliance in the preparation and execution of land agreements to prevent future disputes.