The annulment of contractual deeds in investment relationships gives rise to complex legal consequences, particularly concerning the legal liability of the parties and the fulfillment of rights and obligations previously agreed upon. In practice, investment disputes often arise due to the failure to meet the legal requirements of a valid agreement, defects of consent, or violations of legal provisions that result in a contract being declared null and void or voidable. Such circumstances create legal uncertainty and may cause losses to the parties bound by the contractual relationship. This research aims to analyze the forms and legal grounds of liability in investment disputes arising from the annulment of contractual deeds, as well as to examine their impact on the fulfillment of the rights and obligations of the parties within contractual relationships. The study employs a normative legal research method using statutory, conceptual, and case approaches by examining contract law, investment law, and relevant court decisions. The findings indicate that the annulment of contractual deeds in investment disputes results in legal liability in the form of restoring the parties to their original position (restitutio in integrum), compensation for losses, and the possible emergence of liability based on unlawful acts. The annulment of a contract also affects the termination of contractual rights and obligations, thereby necessitating clear legal regulation regarding the legal consequences of contract annulment to ensure legal certainty and justice for the parties. Therefore, this research emphasizes the importance of prudence in the drafting of investment agreements and the strengthening of the role of law in providing protection and legal certainty in contractual relationships.