The study was conducted to understand the impact of non - performing loans on profitability of Vietnamese commercial banks. Panel data is collected from the published financial statements of 29 commercial banks from 2013 to 2018, and macro variable is collected from the World Bank. GMM model is used to process data. Research result shows that non - performing loans ratio affects strongly and negatively to bank profits, this result is consistent with the theory of bad management and skimming. In addition, internal factors of banks such as total assets, loans on deposits ratio, and loans loss reserves ratio also have the significant impact on profits. Beside that, bank profits is also affected by inflation