Motivational ideas in psychology and their relation to causes are reviewed. Key ideas include hedonism, arousal, rational decision-making, reinforcement, and impulsivity. Motivations proposed for different acts classified as conduct disorder or delinquency are discussed as well as motivational constructs in delinquency theories. It is concluded that theories should include energizing, directing, inhibiting, and decision-making stages at a minimum. Empirical studies of motivations for delinquency that involve asking youth to give reasons for their acts are also reviewed. The most common motivations reported are utilitarian (seeking money or material goods) and hedonistic (seeking excitement or pleasure). It is pointed out that the validity of motivational theories is a separate issue from the validity of verbal reports of motivations. People may be aware of immediate situational motivations but unaware of longer term biological, psychological, or social factors. A program of research on the energizing, directing, and inhibiting of antisocial behavior is recommended and on the relative effectiveness, in reducing conduct disorder and delinquency, of programs targeting these different stages.