The teaching profession is complex and in continuous change. To be able to educate and prepare students for the society of tomorrow, teachers are in need of professional development in order to reflect upon and deepen their understandings of their profession. In this paper, focus is on an informal arena for teacher professional development (TPD) in form of a Swedish online learning community (OLC), called lektion.se. Here some early findings from an ongoing larger study aimed at understanding why and how teachers use lektion.se for their professional development is presented. Special attention is paid on describing the personal and professional background of those members currently working as teachers and frequently using the discussion forums at lektion.se. Finally, a short discussion of lektion.se as an informal online learning community for TPD in order to inform teachers’ everyday life in the Swedish classrooms is provided.