Systems thinking is a holistic approach that puts the study of wholes before that of parts. This study explores systems thinking among school middle leaders – teachers who have management responsibility for a team of teachers or for an aspect of the school’s work. Interviews were held with 93 school coordinators, among them year heads, heads of departments, evaluation coordinators, instruction coordinators, and information and communications technology coordinators. Data analysis revealed that systems thinking among school middle leaders consists of four characteristics: (1) seeing wholes; (2) using a multidimensional view; (3) influencing indirectly; and (4) assessing significance. The findings of this study expand the existing knowledge on systems thinking in school leadership, discussing practical implications as well as further research avenues.