This study aims to analyze the alignment of the regulation on the Notice of Tax Audit Result (Surat Pemberitahuan Hasil Pemeriksaan / SPHP) with the principle of due process of law, and to reconstruct the legal responsibility of taxpayers in the event that an agreement is not reached during this stage. Thus far, the legal relationship between tax authorities (fiscus) and taxpayers at the SPHP stage has tended to be construed unilaterally. The absence of an agreement is frequently deemed an administrative failure on the taxpayer's part, resulting in the passive acceptance of a Tax Assessment Notice (Surat Ketetapan Pajak / SKP) or the necessity to pursue protracted tax litigation. Conversely, tax collection within a constitutional state (rechtsstaat) must be anchored in procedural justice, which guarantees the constitutional right of citizens to a fair hearing (audi alteram partem). The research method employed is normative legal research utilizing a statutory approach and a conceptual approach. The results indicate that, essentially, the SPHP serves as an instrument of preventive legal protection that transforms tax audits from unilateral coercion into an accountable space for legal dialectics. This study argues that legal responsibility for the absence of an agreement at the SPHP stage must not be borne unilaterally; rather, it should be understood as a reciprocal legal responsibility. Taxpayers are obligated to act in good faith by providing true and complete information supported by valid evidence, whereas tax auditors are legally bound to objectively consider all such arguments before issuing an SKP. The failure to reach an agreement does not constitute administrative non-compliance, but rather a legitimate legal dialectic arising from differences in legal interpretation or factual evaluation. Therefore, the lack of an agreement at the SPHP stage must be resolved through the optimization of mechanisms that safeguard procedural justice, such as strengthening the role of the Audit Quality Assurance Team, in order to achieve fair legal certainty.