Enhancing the wellbeing of employees is a key feature of human resource management (HRM) and numerous HRM-practices to strengthen the wellbeing of co-workers have been developed. Although the benefits for the employees of such practices are obvious, the relationship between employee wellbeing and firm performance is unclear. In order to strengthen this relationship some studies have extended the concept of firm performance by including additional "soft" dimensions of performance. However, investing in wellbeing is, of course, associated with costs and several scholars argue that investments in the wellbeing of employees can be regarded as any other investment and from an owner's perspective it is essential to get a return on the investment. In the field of strategic HRM (SHRM), some attempts have been made to analyze the relationship between wellbeing, firm resources and firm performance. Most studies have, however, focused on the relationship between specific HRM-activities and firm performance or certain aspects of resource features. For example, how the wellbeing of employees can enhance the retention of human resources or how wellbeing can stimulate intrapreneurship and thereby generate short-term increases in profits. Thus, few studies have analysed the relationship between wellbeing, competetive advantages and performance from a holistic approach. Consequently, in this paper we present a resource-based analysis of the relationship between the wellbeing of employees and firm performance. We present three propositions regarding the relationship between wellbeing, resources and firm performance. These propositions illustrate the complexity of the relationship by discussing why wellbeing can enhance as well as reduce firm performance.