Dissatisfaction at workplaces points to the low recognition that has been given to the management of psychological contract (PC) which can negatively affect firms’ bottom-line. Made-up of items not found in the employment contract, PC refers to individuals’ beliefs about the terms of the exchange agreement between employers and employees. The study sought to unravel the relevance attached to the subject matter (PC) per its positive effect on job satisfaction (JS) and consequently on competitive advantage (CA) at the three leading audit firms in Ghana. Questionnaires were administered to 150 staff and management of the three selected audit firms. Data obtained were then analysed quantitatively using the Statistical Package for Social Sciences (SPSS). According to the findings of the study, there exists a positive and significant relationship between PC and CA. Also, PC was found to positively and significantly relate to JS, while JS positively and significantly relates to CA. Lastly, JS mediated the relationship between PC and CA. Based on the findings, it is recommended that employees’ expectations should be well defined or explicitly stated and managed by both the organizations and managers. Organizational policies such as annual general meetings with the employees can be avenues for managers to explain the performance of the organization to help employees define their expectations. In addition, free flow of information and frequent formal and informal interactions of managers with their employees can clarify expectations. It is also recommended that managers must be trained on the importance of PC. Managers as well must communicate the organization’s expectations to employees through the use of electronic-HR systems like intranet and internal electronic mail so that they are aware of what the employer wants and how they can contribute in order for the firms to achieve competitive advantage.