The growing threats associated with terrorism and the illicit trafficking of explosives and explosive devices necessitate effective legal regulation of forensic expert activity and the development of international cooperation, including within the frameworks of the EAEU and the CSTO. Despite a common historical background in the development of forensic science, the legal systems of the Republic of Kazakhstan and the Russian Federation have developed different approaches to the procedural and institutional regulation of explosive technical examination. These differences are manifested in the models of organization of expert institutions, the degree of normative detail, and the scope of procedural guarantees for the parties, which creates obstacles to the mutual recognition of expert conclusions and the conduct of joint investigations in cases involving the use of explosive devices. To conduct a comprehensive comparative legal analysis of the regulatory framework governing the appointment, conduct, and evaluation of explosive technical examination in the Republic of Kazakhstan and the Russian Federation, to identify key similarities and differences, and to determine prospects for the harmonization of legal regulation of forensic expert activity. The study employs comparative legal, formal legal, and systemic methods of analysis. The norms of the criminal procedure legislation of the Republic of Kazakhstan and the Russian Federation, special legislation on forensic expert activity, as well as subordinate regulatory legal acts governing the conduct of explosive technical examination, are analyzed. The study establishes that the Russian model of legal regulation of explosive technical examination is characterized by institutional polycentricity and a framework-based regulatory approach enshrined in the Federal Law “On State Forensic Expert Activity in the Russian Federation,” with the existence of several departmental expert systems (Ministry of Justice, Ministry of Internal Affairs, Federal Security Service). At the same time, the model of the Republic of Kazakhstan tends toward institutional monocentricity and more detailed normative standardization, including through professional standards in the field of explosive technical examination. Significant differences are also identified in the procedural rights of the defense when appointing an examination, with the criminal procedure legislation of the Republic of Kazakhstan providing more pronounced adversarial guarantees. The practical significance of the study lies in the possibility of using the findings to improve national legislation and to develop mechanisms for harmonizing forensic expert activity within the EAEU and the CSTO.