For a sustainable competition, it is an important requirement to consider the expectations, needs and thoughts of the employees, who can be described as internal customers as well as external customers. Determining and satisfying these expectations and needs can provide job satisfaction of employees, just like external customer satisfaction. Based on this idea, the ethical values of the organization, which is considered to be effective on job satisfaction, and the perception of brand image in this effect are examined as mediating variable in the present study. In this context, 195 employees of an engineering company that provides production and service at an international level constitute the universe of the research. 147 employees participated in the survey, which was carried out using online survey forms. The findings show that the ethical values adopted by the organization are effective on the job satisfaction levels of the employees and the perceptions of the employees about the brand image have a mediating effect in this effect. The fact that the organization acts within the framework of ethical principles and values increases the sense of belonging of the employees towards their work and organization and may result in them enjoying working together. In addition, it shows that as the sensitivity of the organizations on ethical principles and values increases, the brand image gains strength in the minds of the employees and thus the pleasure they feel from their work increases. It is recommended that organizations to inform employees about ethical values from time to time and that the effects of brand image on employees through different organizational variables should be observed in future researches.