This article reports on an investigation of children's definitions of the truth that can pertain to their ability to provide accurate information during an investigation or trial: whether corroborating an inaccurate statement made by a parent is lying or telling the truth. Subjects were 133 preschool through third-grade children who were shown a videotape in which either a boy makes a false statement to a neighbor about the neighbor's daughter hitting him and his mother listens passively or a mother makes a similar false statement and the boy corroborates it. None of the children classified the corroboration as the truth. Only a small percent of the preschool and kindergarten children classified the boy's or mother's initial false statement as the truth; all of the older children classified these statements as a lie. About 20% of the children recalled incorrectly that the neighbor's daughter hit the boy.