Individuals and society invest ever-increasing resources in formal educational programs. However, informal workplace learning may be an effective alternative source for enhancing competencies, but, unfortunately, our knowledge about informal learning is still limited. We extend the research on informal learning to the unexplored occupational group of kindergarten employees. Our research questions pertain to identifying activities that lead to informal learning, to conditions that promote or prevent such learning, and to differences between two groups of employees (preschool teachers and assistants). We used a qualitative case-study approach and conducted semistructured, in-depth interviews in a Norwegian kindergarten. The data indicated that the participants were involved in a variety of learning activities. However, preschool teachers and assistants differed regarding the conditions for informal learning, with assistants perceiving greater barriers to learning in the workplace. We argue that the assistants are easily trapped in situations in which further learning is diffi cult, and, paradoxically, those employees with the lowest formal education also seem to be disfavored with regard to informal learning. Clever organization of the work and careful leadership might be key actions to break through this invisible learning ceiling.Key Words: informal learning, workplace learning, learning activities, barriers to learning, educational level, kindergarten, preschool teachers and assistantsThe need for knowledge seems to be constantly increasing, with individuals, organizations, and society investing enormous resources in educational programs. Even so, this kind of formal learning is only one source of developing 300 Schei, Nerbø HUMAN RESOURCE DEVELOPMENT QUARTERLY • DOI: 10.1002/hrdq competency, as employees also learn during the execution of work. Such informal workplace learning may take place, for example, through discussions with colleagues, by experimenting with new methods, or during the observation of others (e.g., Hoekstra, Korthagen, Brekelmans, Beijaard, & Imants, 2009;Koopmans, Doornbos, & van Eekelen, 2006;Lohman, 2005). Interestingly, research has estimated that as much as 80% of what employees learn actually stems from informal workplace learning (Marsick & Watkins, 1990) and that many of the most critical skills are obtained through such learning (Cameron & Harrison, 2012;Crossan, Lane, & White, 1999;Eraut, 1994;Leslie, Aring, & Brand, 1998). Informal learning is also far less expensive than formal training (Boud & Garrick, 1999;Lohman, 2005).However, despite the prevalence and the potential importance of informal learning, our understanding of how it occurs and what infl uences such learning is still limited (Ellinger, 2005;Koopmans et al., 2006). The intention of the present study is to extend the research on informal learning to the unexplored occupational group of kindergarten employees. Examining informal learning among kindergarten employees is particularly interesting for several reasons. F...