<![CDATA[This research is motivated by developments in national criminal law following the enactment of Law Number 1 of 2023 concerning the Criminal Code, which establishes the lex favor reo principle in Article 3. This principle mandates the application of the law most favorable to the defendant in the event of changes to legislation. Meanwhile, the rise of digital sexual crimes specifically child grooming presents a legal issue, as the act is not explicitly regulated in the National Criminal Code. This situation creates a dilemma between protecting the defendant's rights via the principle of legality and the need to protect children from digital sexual exploitation. Accordingly, this research addresses two issues: (1) the regulation of the lex favor reo principle within the National Criminal Code, and (2) the application of the lex favor reo principle to the crime of child grooming under the National Criminal Code. The study employs a normative-juridical research method, utilizing statutory, conceptual, and case-based approaches. Legal materials include primary sources (legislation), secondary sources (legal books and journals), and supporting tertiary sources. The findings indicate that the lex favor reo principle in the National Criminal Code serves as a safeguard for human rights and substantive justice, requiring the application of the most lenient law to the defendant. However, applying this principle to child grooming reveals a normative gap, as child grooming is not explicitly defined as a specific criminal offense. Therefore, a reformulation of national criminal law is required one that is more adaptive to the evolution of digital sexual crimes to ensure legal certainty while providing maximum protection for children.]]>
