Transactions on Economic and Business Models Diep Ngoc Duong, Lien Thuy Le Nguyen, Phuong Ngoc Thi Huynh 1 1 2025 https://doi.org/10.6025/tbem/2026/1/1/24-38 https://www.dline.info/tebm/fulltext/v1n1/tebmv1n1_3.pdf This study investigates the impact of adopting International Financial Reporting Standards (IFRS) on financial reporting quality within emerging economies, specifically focusing on ASEAN nations. We examine the interplay between accounting standards (ACST), accounting disclosure quality (ADQ), sustainability reporting quality (SRQ), and their influence on firm market value (FMV). Utilizing a panel dataset of 3,211 firmyear observations from ASEAN-based companies between 2019 and 2023, sourced from Thomson Datastream, we employ quantitative techniques to analyze the relationships. Our findings reveal a significant negative association between SRQ and FMV, while ADQ exhibits a positive relationship with FMV. Furthermore, ACST plays a crucial moderating role, influencing the ADQ-FMV and SRQ-FMV relationships. These findings lend credence to agency theory, suggesting that adopting IFRS can mitigate agency problems, benefiting stakeholders through enhanced corporate transparency and financial performance. This research contributes to the ongoing discourse surrounding IFRS adoption, offering valuable insights for policymakers, investors, and academics alike. We conclude by acknowledging the limitations of our study and outlining potential avenues for future research.