Videotaped stories depicting deliberate lies and unintentionally untrue statements were presented to 200 subjects evenly divided into the following age groups: 5, 8, 9, and 11 years and adult. Definitions of lying were seen to change gradually over this age range. Adults were more lenient than children in their moral evaluations of all the statements. All age groups rated a guess that did no harm as better than one that caused trouble, and they all judged selfishly motivated lies to be worse than both unintended falsehoods and "jocose" lies that aimed to please the listener. 11-year-olds tended to justify the prohibition against lying in terms of trust and fairness, whereas younger children cited authority's punitive sanctions.