The principle of legality constitutes one of the basic principles of the government’s rule of law, and as a result, it has been recognized as one of the most essential guarantees of human rights. The goals of sustainable development have a strong link with the principle of legality, and achievements in accomplishing a goal can frequently contribute to the accomplishment of other goals in addition. The United Arab Emirates’ constitutional framework, regulations, and rules, along with the goals for sustainable development (SDGs), were profoundly affected by the principle of legality. The method in which international standards and laws have been integrated into the UAE’s national legal framework provides definitive proof of this effect. The research concluded that all published and unofficial legal regulations have to be respected in order for public authorities to use within the limits of the principle of legality. These involve adhering to the standards of positive legitimacy and the fundamental regulations the community agrees on.

ESG (environmental, social and governance, a framework used to assess an organisation’s business practices and performance on various sustainability and ethical issues) and Digital Transformation (the process of using digital technologies to change a business’s operations, products and services by integrating digital solutions into all areas of the business, which can lead to cultural and technological changes) are emerging issues across different industries, including the banking field. There has been limited research focusing on exploring the linkages between ESG, Digital Transformation and Customer Behaviour in the banking area, especially within developing countries such as Vietnam. Based on this gap, this study analyses and assesses the role of Digital Transformation and ESG on customer behaviour towards brands in the banking sector in Ho Chi Minh City. The research employed the quantitative research methods with the combination of fundamental analytical methods such as statistics, Cronbach’s alpha reliability, Exploratory Factor Analysis (EFA), measurement models and Partial Least Squares Structural Equation Modelling (PLS-SEM). The analysis was based on survey data from 550 customers who are the commercial banks’ current customers and live in Ho Chi Minh City, yielding 514 valid responses. Using SPSS and SMART PLS software, the study provided notable results. Specifically: (1) The component factors of ESG, including Environmental Issues (EN), Social Issues (SO), Government Issues (GO) and Digital Transformation (DT), positively influence Customer Behaviour (CB); (2) The component factors of ESG, including Environmental Issues (EN), Social Issues (SO) and Government Issues (GO), play a mediating role in the relationship between Digital Transformation (DT) and Customer Behaviour (CB).