Revenue recognition is a very complex area due to user interest in this metric and can even lead to errors and fraud in its understanding. The difficulties of revenue recognition are well known to practitioners because, even if the principles and standards are stable, economic conditions may require new experiences, adaptive knowledge, and flexibility. Therefore, thinking about how to apply the new IFRS 15 standard is more important than ever as the transition to the new standard takes place. In this context, this study aims to evaluate the way external auditors understand how implementing IFRS 15 will probably affect business performance and profitability, and to identify the main problems and obstacles that could come up during that process. In this sense, a quantitative study was conducted using a survey of auditors working for Big Four companies during 2021–2022. To address these problematic aspects of revenue disclosure under the standard, the study’s findings look into how external auditors perceive the complexity of IFRS 15, the openness of their professional judgment, and the anticipated advantages of engagement activities. In addition, the literature review identified business sectors that demonstrated a significant impact on revenue recognition as a result of the implementation of IFRS 15.