While a lot is known about teacher development by means of formal learning activities, research on teachers’ everyday learning is limited. The current systematic review study analyzes 74 studies focusing on teachers’ informal learning in order to identify teachers’ learning activities, antecedents for informal learning, and learning outcomes. In addition, this study examines if differences exist between beginning and more experienced teachers with regard to informal learning. Results reveal different types of learning activities and interesting relations among different antecedents and various learning outcomes. Moreover, it can be concluded that the main difference between beginning and more experienced teachers does not lie in the type of learning activities they undertake. Rather, their attitudes towards learning, the outcomes of learning, and how they are influenced by their context differs.