Using an information-processing approach and organisational learning theory (i.e. ambidexterity), the current innovative study examines a model for the prediction of schools' collective mindfulness and its consequences, linking principals' cognitive complexity (CC) with school ambidexterity and mindfulness, school ambidexterity with school mindfulness, and the effect of school mindfulness and ambidexterity on a teacher's psychological capital. The study further examines the indirect effect of principals' CC on a teacher's psychological capital through the effects of ambidexterity and mindfulness. Participants were 104 principals and 1002 teachers from 104 Israeli schools. Results showed that school mindfulness is affected by principals' CC and school ambidexterity, and that school mindfulness and school ambidexterity relate directly and positively to a teacher's psychological capital. Finally, school mindfulness and ambidexterity connected school principals' CC to a teacher's psychological capital. This study adds to the body of research directed at identifying leaders' roles and work-related factors that may positively affect organisational mindfulness and a consequence of school mindfulness, i.e. a teacher's psychological capital, and that are amenable to leadership intervention.