The main purpose of this study is to scrutinize the effect of financial inclusion on financial sustainability, financial efficiency, gross domestic product, and human development in the context of G20 nations. This study has employed annual data of 15 developed and emerging economies during the period from 2004 to 2017. The current study has utilized a single index for financial inclusion, financial sustainability, and financial efficiency by employing principal composite analysis (PCA). The outcomes of the panel stationarity test confirmed the ARDL model for both the long and short runs. Equally, the findings of the ARDL Model 1 showed no association between financial inclusion and financial sustainability in the short run, however, in the long run, inclusive finance showed a significant impact on sustainability. Likewise, the ARDL Model 2 showed that financial inclusion has no effect on efficiency in the short run, while it positively influenced financial efficiency in the long run. The results of the ARDL Model 3 are also similar to Models 1 and 2 where inclusive finance showed no effect on poverty in the short run, but a significant effect in long run. Similarly, the ARDL Model 4 also presented no association between GDP and inclusive finance in the short run, while it showed significant relationships in the long run. Moreover, the outcomes of the GMM Model 1 showed a significant impact of inclusive finance on financial stability, and these results were similar to the GMM Model 2 between financial inclusion and financial efficiency. Additionally, GMM Models 3 and 4 have shown that inclusive finance has a statistically significant impact on poverty and economic expansion, respectively. The outcomes of this article are essential for policymakers, academics, regulators, and practitioners with valuable and convincing debate over financial inclusion, economic growth, poverty, sustainability, and financial efficiency.