Teachers are drivers for change in school improvement. However, not all teachers participate in further
developing schools' educational practice. This study aimed to understand conditional factors in teachers'
involvement. To this end, we analyzed teachers' leadership perception and boundary-crossing activities
aimed at increasing professional capital. Structural equation modeling analyses based on a sample of
N ¼ 1232 teachers at N ¼ 59 schools indicated partial mediations of cognitive and social boundarycrossing activities on the relationship between leadership perception and involvement. This study
contributes to the literature by illuminating the potential of teachers’ activities to enhance professional
capital for school improvement.