Purpose - The purpose of this paper is to explore informal contexts of teachers' workplace professional learning and inform educational researchers, teacher educators, administrators and teachers about ways in which teachers learn to improve their practice. By questioning how teachers learn on-the-job to be better teachers and how school cultures position them as learners, this study seeks to generates hypotheses about relationships between the nature of workplace professional learning and its content and informal contexts. Design/methodology/approach - An ethnographic design based on a grounded theory generates analytic categories from interviews, participants' reflective journals and field notes through comparison of learning environments in three contrasting schools in two countries - Lithuania and the USA. Discourse analysis is employed to analyze three cases of the schools' informal learning contexts in order to better understand how teachers learned through everyday interactions. Findings - Within each case, the findings illuminate three facets of school culture that provide or fail to provide opportunities for teacher learning in informal contexts: school leadership, teachers' professional relationships, and their individual stances as learners. Research limitations/implications - The limitations of the paper derive from its focus on school cultures as learning organizations producing detailed thick descriptions, which are culturally specific and may not necessarily be transferable to other schools. Practical implications - The implications underline that teachers and teacher educators could enhance teachers' professional learning by contributing to building and sustaining the opportunities necessary to maintain professional growth at teachers' workplaces. Originality/value - The value of the paper is in: defining specific cultural features in schools that create or fail to create opportunities for teachers to learn informally; showing how teachers use these opportunities for their learning; calling for re-evaluation of professional development systems to include informal learning as an important path for professional growth.
