Two studies examined I92 maltreated young children's competence to take the oath.  Study I found that despite serious delays in receptive vocabulary, a majority of 5-year-olds correctly identified truthful statements and lies as such and recognized that lying is bad and would make authority figures mad. However, most participants up to 7 years of age could not define "truth" and "lie" or explain the difference between the terms. Four-year-olds were above chance in recognizing the immorality of lying but exhibited a tendency to identify all statements as the "truth. " Study 2 found that 4- and 5-year-olds performed above chance in identifying which of 2 story characters was lying or telling the truth and in identifying whether the truth-teller or the liar said something bad or would get in trouble. Children exhibited better understanding of the immorality of lying than the meaning of lying. Maltreated children's oath-taking competence may be underestimated due to linguistic and motivational difficulties.