New technologies such as social media has rapidly expanded the organizational need for new knowledge and ability to quickly adapt to a changing environment in order to keep up with competitors. This also puts pressure on organizational members to gain new competence and knowledge and to be able to learn these new technologies in a workplace environment. Organizations often spend time and resources on formal training and education. However, the development of new technologies such as social media has enabled employees to learn anywhere and anytime. Web 2.0 technology and social media technologies in particular allows researchers to shed a new light on the importance and occurrence of both formal and informal learning in the workplace. Unlike the technologies employees may encounter in organizational settings, social media has proliferated outside organizational contexts prior to being introduced to the workplace. Formal learning is often described as planned and structured and often takes place outside of the workplace, while in contrast, informal learning often is described as unstructured and non-institutionalized. Informal learning is also often linked to tacit knowledge, learning by doing and a result of everyday workplace activities. A large amount of studies revealed that the majority of workplace learning occurs through informal means. While there is growing evidence that social media is increasingly supporting informal learning at home, there are few empirical studies that support the claim that organizational social media enables informal learning in the workplace. The present study investigates the relationship between both formal and informal workplace learning and organizational social media. Earlier research on social media use in organizational settings has mainly focused on the use of specific social media platforms and also made clear distinctions between internal and public use of social media. A key gap in the literature on social media is a lack of analysis that considers more overall use and impact of all these social media uses on the organization. Hence, this study take the approach of using the perspective of organizational social media in order to embrace a more general use of social media in an organizational context. For this purpose, a longitudinal case study has been conducted over five years (2013-2018) within an international hotel chain. The data collection is based on 43 interviews (including 17 follow-up interviews) with hotel employees who are using and who is in charge of the social media use in 14 hotels within the international hotel chain. In addition, data from online observations, workplace observations and written documents has been collected. The following research question has been asked: 1) When does formal and informal learning occur in the workplace? 2) How does the employees formal and informal learning effect the organizational social media use over time ? The results showed that the employees had little interest in the formal learning that was offered by the hotel chain management and that informal learning occurred related to job-related activities, often related to un-expected situations. Furthermore, the study showed that that the employees personal drivers for informal learning highly effected how they used social media in their workplace.