Children's lie-telling behavior and its relation to false-belief understanding was examined in children with autism spectrum disorders (ASD; n = 26) and a comparison group of typically developing children (n = 27). Participants were assessed using a temptation resistance paradigm, in which children were told not to peek at a forbidden toy while left alone in a room and were later asked if they peeked. Overall, 77% of the total sample peeked at the toy, with no significant difference between the ASD and typically developing groups. Whereas 96% of the typically developing control children lied about peeking, significantly fewer children with ASD (72%) lied. Children with ASD were poorer at maintaining their lies than the control group. Liars had higher false-belief scores than truth-tellers. These findings have implications for understanding how theory of mind deficits may limit the ability of children with ASD to purposefully deceive others. (Contains 1 table.)