In this comprehensive study of the early development of guilt, 106 children were observed in laboratory paradigms in which they were led to believe that they had damaged valuable objects, during two separate sessions at each of the assessments at 22, 33, and 45 months. The behavioral and affective components of guilt cohered significantly across the sessions, converged with each other, were stable across all the assessments, and corresponded modestly with maternal reports. Most components decreased with age, except for bodily tension, which increased. At 33 and 45 months, girls displayed more guilt than did boys. Children who were more fearful in typical fear-inducing paradigms also displayed more guilt. Children of mothers who relied on more power-assertive discipline, observed and self-reported, displayed less guilt. Guilt related positively to the development of self at 18 months and to moral self at 56 months. Children who displayed more guilt were less likely to violate rules of conduct at 56 months. A mediational model was supported: Fearful temperament contributed to guilt proneness, which in turn served to inhibit children’s tendency to violate rules.