The aim of this article is to identify the main principles governing the interpretation of domestic law clauses that grant jurisdiction to ICSID arbitration and to analyse the meaning of such provisions in the context of the SPP v. Egypt case as the first case on the issue. The article first examines the peculiarities of consent to ICSID jurisdiction by way of national legislation. In the first part the analysis of the practice of arbitral tribunals in which a claim was introduced on the basis of consent to arbitration in domestic law shows that specific language of national legislation on consent to arbitration varies considerably. Therefore, since consent is the “cornerstone” of the Centre’s jurisdiction, arbitral tribunals recognize that not all references to ICSID arbitration in national legislation amount to consent. They approach the task of ascertaining the existence of such consent with great care. In the second part, the article focuses on the SPP v. Egypt case on the issue and analyses challenges that the tribunal met in interpreting relevant national clauses and establishing the consent to arbitration. Finally, this article discusses the legacy of interpretation standard of SPP v. Egypt case in context of the dissenting opinion and further case law. It is argued that the rules of interpretation of domestic law clauses that grant jurisdiction to ICSID arbitration are conditioned by the sui generis nature of consent to arbitration as unilateral declarations capable of giving rise to international legal obligations. Therefore, for the purpose of establishing whether there is consent to arbitration provided in national legislation, international tribunals reasonably take a balanced approach and use the methodological mix of rules of interpretation involving various sources: the VCLT, customary law principles governing unilateral declarations and domestic legislation. Additionally, this article provides suggestions on the possible role of the Guiding Principles applicable to unilateral declarations of states capable of creating legal obligations (Guiding principles) in interpreting domestic provisions containing an offer to arbitrate before ICSID.