Personal income tax (PIT) on salaries and wages is an important source of state budget revenue and an instrument for achieving social equity. In Vietnam, this area is governed by the Law on PIT and its implementing regulations. However, practical application still raises several issues relating to the determination of taxpayers, deductions, tax brackets, and mechanisms for tax withholding, declaration, and finalization. Using legal research, analysis, and comparative legal methods, this article analyzes the legal framework governing PIT on salaries and wages, thereby identifying limitations concerning the reasonableness of the tax brackets, deduction mechanisms, and the effectiveness of tax administration. On this basis, the article proposes several solutions to improve the legal framework towards ensuring fairness, simplifying compliance obligations, enhancing administrative efficiency, and ensuring consistency with Vietnam’s socio-economic conditions.