Listening to employees’ concerns reduces their dissatisfaction, but moreover, for an organization to achieve sustainable success, employees must raise their creative voice and give their input in decision-making without the fear of rejection in a psychologically safe environment. Ethical leaders facilitate such a participative style of management. A bureaucratic culture, as is generally encountered in Pakistan’s work settings, poses real challenges to those who dare to speak up, therefore the importance of ethical leadership, leader–member exchange (LMX), and psychological safety cannot be neglected as coping mechanisms to sustain the employee voice for mutual gains. To investigate ethical leadership’s mediating mechanisms and boundary conditions on voice behavior, we examined a moderated mediation model with the leader–member exchange as a moderator and psychological safety as a mediator. Grounded in social exchange theory (SET), the current study uniquely posits and tests that employees feel psychologically safe in the presence of an ethical leader with whom they have high-quality social exchanges. Data were collected from 281 employees from the public corporations and private enterprises of the petroleum sector of Karachi. Results of the analysis, through SPSS and AMOS, revealed that psychological safety mediated the relationship of ethical leadership and voice behavior, while the indirect effect of ethical leadership on voice behavior (via psychological safety) is stronger for those employees who enjoy high-quality exchanges with ethical leaders. LMX was also found to moderate the relationship between ethical leadership and voice behavior. Contributions, recommendations, and limitations of the current study and further research areas are also discussed. The study offers practical insight on the mechanism of ethical leadership on employee voice behavior and recommends leaders to develop social exchanges to improve voice behavior for sustainable success.