Over the past quarter-century, schools and school districts have become increasingly turbulent, pluralistic and unpredictable places to lead. On any given day, conflicting values, ideas, preferences, interests, needs, demands, problems and solutions descend upon the typical school leader from a shifting array of individuals and groups, each with fluctuating degrees of influence and power. As a result, many administrative decisions are based on beliefs concerning the likelihood of uncertain events. This article contains 15 cognitive traps common to managers in all types of organizations, but especially schools. They are derived from the large body of literature on both educational and private-sector managerial decision making. It should be noted there are no fail-safe strategies that can help leaders avoid or reduce the damaging effects that such traps so often inflict upon decision-making processes and their outcomes.