The order of dismissal without prejudice (non-hearing of the lawsuit) is a type of formal definitive decision where the court refrains from entering into the merits, refraining from proceedings due to the lack of legal conditions for hearing the case or the existence of a normative obstacle. This institution, unlike an order of dismissal with prejudice (rejection of the lawsuit) which implies the determination of the plaintiff's lack of right, pertains to the refusal of substantive consideration due to the conflict of the lawsuit with mandatory rules, public order, or jurisdictional and contractual requirements. The present research, adopting an analytical-descriptive approach and relying on legal doctrine and judicial practice, examines the foundations for issuing this order in Iranian law. The findings indicate that the most significant grounds for issuing a non-hearing order include: the conflict between the subject matter of the claim and mandatory laws or registration regulations; the necessity to safeguard the potential rights of third parties; the validity of arbitration agreements and contractual stipulations based on the principle of party autonomy; the futility of the proceedings and the lack of practical effect of a judgment; and the priority of quasi-judicial authorities and the requirement to follow the prescribed legal procedure. At the same time, distinguishing between irremediable substantive obstacles and remediable procedural objections requires the court, within the framework of the principle of access to justice, to refrain from unjustifiably expanding the scope of this order.