Our inability to predict the effects of hierarchical leader behaviors consistently might be due to subordinate, task, or organizational characteristics that serve as “neutralizers of” or “substitutes for” hierarchical leader behaviors (Kerr & Jemier, 1978). Neutralizers are variables in leader’s environment that effectively eliminate the impact of a leader’s behavior on subordinate outcome variables, but do not replace the impact of such behavior with an effect of their own. Substitutes are special types of neutralizers that reduce a leader’s ability to influence subordinates’ attitudes and performance and that effectively eliminate the impact of a leader’s behavior with one of their own. Potential neutralizers or substitutes include subordinate characteristics (e.g., their ability, experience, training, or knowledge), task characteristics (e.g., intrinsically satisfying task; routine, invariant task; task feedback), and organizational characteristics (e.g., rewards outside the leader’s control, rule inflexibility, work group cohesiveness). Reliable, construct-valid measures of such “Substitutes for Leadership Scales” are now available (Podsakoff & MacKenzie, 1994). If it were possible to identify factors that may moderate the effect of leader behaviors on subordinates’ attitudes, behavior, and perceptions, this would explain why some leader behaviors are effective in some situations, but not in others. It is the task of future research to determine whether these sorts of moderating effects really do exist.