Penelitian ini bermaksud menjawab dua pertanyaan terkait perzinahan dalam kitab Undang-Undang Hukum Pidana (KUHP) dan hukum adat Dayak Abai. Pertama.. Bagai mana perzinahan menurut ketentuan kitab undang-undang hukum pidana (KUHP) dan hukum adat Dayak Abai? Kedua, perbandingan hukum antara sanksi dalam kitab undang-undang hukum pidana KUHP dan hukum adat Dayak Abai mengenai perzinahan. Skripsi ini merupakan penelitian normatif terhadap kaidah- kaidah hukum terkait variabel penelitian. Penelitian ini menggunakan pendekatan Konseptual (Conceptual Approach), yakni: Pendekatan konseptual di laksanakan dengan melihat peraturan perundang-undangan dan dokterin-doktrin hukum ataupun pandangan hukum guna menemukan konsep ataupun ide serta asas hukum yang berkaitan dengan masalah dalam penelitian ataupun menjadi solusi dari permaslahan dalam penelitian. Dan pendekatan Perbandingan (Comparative Approach), yaitu: jenis pendekatan yang mencoba membandingkan peraturan hukum satu dengan hukum lainnya didalam sistem hukum suatu negara. Hasil dari penelitian ini, penulis menyimpulkan bahwa: pertama, perzinahan dalam KUHP dan Hukum Adat Dayak Abai memiliki pandangan yang sama sedangkan KUHP 2023 memiliki pandangan berbeda. Kedua, Tujuan pemidanaan dalam KUHP menekankan pada tujuan Retributive dimana hukuman diberikan sebagai bentuk pembalasan kejahatan yang diperbuat sipelaku kejahatan. Kemudian dalam KUHP 2023 menekankan pada pemulihan, pembinaan, pembimbingan, memperbaiki kesimbangan akibat timbulnya konflik, serta menumbuhkan rasa penyesalan dan membebaskan rasa bersalah dari terpidana. Sedangkan dalam hukum adat Dayak Abai lebih menekankan hukman sebagai bentuk pemulihan kekeadaan semula, upaya penggantian kerugian, serta upaya pencegahan terhadap pengulangan perbuatan.

Kata kunci: Hukum Adat Dayak Abai, Hukum Pidana, Perzinahan.

The primary objective of this study was to address two inquiries on the subject of adultery within the context of the Criminal Code and Dayak Abai customary law. Firstly, it is imperative to ascertain the definition of adultery as outlined in both the Criminal Code and the customary law of Dayak Abai. Furthermore, this analysis aims to provide a legal comparison between the sanctions outlined in the Criminal Code and the Dayak Abai community's customary law with respect to adultery cases. The present study constitutes normative research examining legal regulations on research variables. Utilizing a Conceptual Approach involves an examination of statutory laws, legal doctrines, and legal perspectives to identify relevant concepts, ideas, and legal principles that pertain to research issues or offer potential resolutions to research challenges. The Comparative Approach is a methodological approach that seeks to analyze and evaluate the similarities and differences between a specific legal regulation and other regulations within the legal system of a certain country. The study's findings indicate that both the Criminal Code and the Dayak Abai Customary Law have a similar perspective on adultery, however, the proposed 2023 Criminal Code presents a contrasting viewpoint. As the Criminal Code outlines, punishment's primary objective is to prioritize retributive aims. Punishment serves as a means of resolving criminal offences perpetrated by the individual responsible. In contrast, the revised Criminal Code of 2023 places significant emphasis on rehabilitation, guidance, mentorship, and restoring equilibrium in response to instances of conflict. Moreover, it seeks to cultivate a sense of remorse and alleviate the burden of guilt experienced by the offender. In contrast, the customary law of Dayak Abai lays a greater focus on the utilization of punishment as a means of reinstating the initial state, facilitating compensation for incurred losses and deterring the recurrence of the transgression. Keywords: Dayak Abai Customary Law, Criminal Law, Adultery