Since 2005, the International Financial Reporting Standards (IFRS) mandatory adoption in the European Union has played a pivotal role to reduce financing costs which has influenced positively economic growth across member states. Thus, this study examines the effect of Cost of Capital on Economic Growth under IFRS mandatory adoption in 17 European countries between 1994 and 2021 using Pooled Mean Group Autoregressive Distributed Lag (PMG-ARDL) and System Generalized Method of Moments (GMM-system) methods. The findings reveal a positive correlation between the Cost of Capital and Economic Growth under IFRS adoption. Specifically, the model estimates indicate that the Cost of Capital contributes to a 0.58% increase in Economic Growth in the PMG-ARDL framework. Moreover, the GMM-system model underscores the significance of IFRS adoption in reducing the Cost of Capital, leading to a 0.52% increase in Economic Growth. These results provide insights into the benefits of adopting international accounting standards and highlight the importance of institutional and financial factors in shaping the economic impact of adopting accounting standards.