Multiple factors have contributed to the burgeoning emphasis on Corporate Social Responsibility (CSR) within the Vietnamese banking sector. There is a burgeoning consciousness among consumers and stakeholders regarding the significance of sustainable and ethical business practices. With increasing social awareness, customers are progressively opting to support businesses that are dedicated to CSR. Moreover, regulatory entities in Vietnam have initiated measures to encourage CSR practices among banks. This study underscores the profound impact of CSR on the financial performance of the banking sector. The authors developed hypotheses to find out the determinants of the financial performance of Big 4 banks in Vietnam by collecting secondary data in the 2017-2022 period. To answer this question, the Person test, Pool OLS, FEM, REM and FGLS models were used, and then the Hausman test, Wald test and Wooldridge test were used to test the suitable model. The research showed that financial performance in the Big 4 banks in Vietnam (Vietcombank, BIDV, VietinBank, and Agribank) was negatively impacted by capital ratio and financial leverage and positively and significantly influenced by corporate social responsibility and overhead expenses. Thus, by integrating CSR initiatives into their business strategies, banks can enhance their reputation, attract socially conscious customers, and improve return on assets (ROA). Overhead expenses are another key factor significantly impacting a bank's ROA. The Big 4 banks should focus on optimizing their cost structure by identifying and eliminating inefficiencies in their operations. Implementing digitalization initiatives, streamlining processes, and investing in technology can reduce overhead expenses and improve operational efficiency. From these results, the paper gave recommendations for banks to improve their financial performance.