Attributional complexity refers to the capability of discriminating and integrating dimensions related to social judgment in order to understand social behaviour. While previous leadership research has examined the role of leader attributions, it has neglected the role of attributional complexity. We theorize and find support for a relationship between higher attributional complexity and transformational leadership behaviours, based on a sample of 100 leaders and their direct reports. Leaders who were more complex in their social judgments, attributing complex external and internal causes to others' behaviours and actions, were seen as more transformational by their direct reports. Our findings suggest that attributional complexity is a construct that warrants consideration in future research on both transformational leadership and leadership attributions.