This paper reports an investigation into the strategic thinking skills of school leaders in Hong Kong. By adapting the Strategic Thinking Questionnaire in the school context and based on data self-reported from 543 Hong Kong school leaders, three cognitive capabilities with strategic thinking were identified: reflection, systems thinking and reframing. The study determined that (a) the use of the strategic thinking could distinguish between more and less successful leaders, (b) school leaders' understandings of system dynamics had significant effects leadership effectiveness, and (c) while systems thinking explained much of the variance in the success variable, there was a cumulative impact of the use of all three capabilities. These findings have implications for training, professional development, and selection of aspiring leaders. [For complete volume, see ED567040.]