The main focus of this study is preschool teachers’ own learning from a specific course aimed to develop their knowledge of how to use learning study (LS) in preschool. The study included 24 qualified and experienced preschool teachers who took part in the course. The course was funded by the Swedish National Agency for Education and the teachers were chosen by their municipal employers. An analysis is made of their experiences of the in-service course on LS and variation theory. The 24 preschool teachers were divided into seven groups, each of which implemented one LS. A total of 162 preschool children participated. After the course, the participants were asked, “How do you think LS can contribute in preschool?” Their answers were analyzed, and six qualitatively different categories were found, capturing their different perspectives. In the studies reported in this chapter, the results of the children's learning outcomes are also briefly reported to offer readers a background understanding of the teachers’ experiences. The children's learning outcomes did all show an improvement. In describing their experiences of the in-service training using LS, all of the 24 participating preschool teachers reported that their understanding of children's learning had changed and improved. They specifically mentioned having a stronger focus on content than before, seeing the difference between learning and method by separating them, and focus on the learning of a defined content in the first place.