We investigate the effects of financial development on income inequality for a global sample of countries between 1980 and 2019. The study contributes to the current literature by first, making use of a multifaceted index of financial development that captures different aspects of financial developments over time. Second, we compare the effects of financial development on income inequality across economic classifications, namely advanced, emerging and least developed countries. Last, we investigate the non-linear effects of financial development on income inequality across these economic classifications. The findings indicate that in general, financial development reduces inequality across emerging and least developed countries, but is not statistically significant for advanced countries. However, when we disaggregate the financial development index into its sub-components (financial institutions and financial markets), we find different effects on inequality, based on the levels of development. Further investigation on the dimensions under financial institutions and financial markets (depth, access and efficiency) reveals that banking sector development under financial institutions has income inequality-reducing effects in emerging and least developed countries, while stock market development under financial markets widens inequality in least developed countries. We also find heterogeneous non-linear effects between emerging and least developed countries. The findings in our paper firstly highlight the nuances in financial development depending on the level of development in countries, and secondly that policies focused on financial inclusion of the poor can mitigate inequality.