T This study aims to analyze and describe the legal framework governing the determination of customs value as the basis for calculating import duty under law number 17 of 2006 concerning customs, as well as to examine the obstacles and challenges encountered by the directorate general of customs and excise in determining customs value and their implications for the emergence of customs disputes under law number 17 of 2006 concerning customs and the minister of finance regulation number 144/pmk.04/2022 concerning customs value for the calculation of import duty, using tax court decision number put-003886.19/2024/pp/m.xviia of 2025 as a case study. this research employs a normative legal research method with a descriptive-analytical approach, applying both the statutory approach and the case approach. the study is supported by secondary data consisting of primary and secondary legal materials obtained through library research and analyzed qualitatively. the findings indicate that the determination of customs value places the transaction value as the primary basis for customs valuation, as stipulated in articles 15 to 17 of law number 17 of 2006 and further elaborated in minister of finance regulation number 144/pmk.04/2022, through the sequential application of customs valuation methods. accordingly, the use of alternative valuation methods, including the fallback method, is only justified where the rejection of the transaction value is based on objective and legally justifiable grounds. the obstacles and challenges in determining customs value arise from differences in the assessment of the validity of the transaction value, issues concerning documentary and payment verification, the use of comparison data, special relationships between the parties, and the limited transparency in the application of alternative valuation methods. these factors ultimately contribute to the emergence of customs disputes, as reflected in the tax court decision, which granted the importer\\\'s appeal in its entirety.