Culture is a key determinant in organizational effectiveness and plays an enormous role in the lives of military organizations. Cultural biases often result in unstated assumptions that have a deep impact on strategy, operational planning, doctrinal creation, and organization and training of armed forces. The impact of culture on military affairs often remains opaque for years, if not decades, after the events it has affected. Leadership is essential to creating and maintaining organizational culture. Leaders who can shape an organization’s culture from its inception have an outsized influence on its future orientation. Leaders, therefore, must be discriminating when establishing the initial culture of an organization, for once embedded, that culture will prove extraordinarily difficult to change. But even superb leaders are limited. Selection of the right subordinate leaders is critical if an organization’s culture is to survive a leadership transition. Some military organizations do change, assisted by cultures that embrace innovation and a reasonable degree of risk-taking. Organizational culture takes on the characteristics of wider societal culture, but when the military becomes a caste apart, the result can be the degradation of its ethical foundations. Military organizations often have subcultures with significant influence on the larger organization. Technology-centric forces must not allow a culture focused on technological excellence to turn into one centered on technological determinism. Professional military education is critical in sustaining organizational culture.