Objective: Children with ADHD overestimate their own social and behavioral competence when using explicit self-report measures, a phenomenon known as Positive Illusory Bias (PIB). This study examined whether children with ADHD show PIB when self-perceptions are measured implicitly, reflecting associations that are relatively difficult to consciously control. Method: Participants were 23 children (ages 6.8-9.8) with ADHD and 55 typically developing (TD) children. Children’s explicit self-perceptions of competence were measured via self-report on the Self-Perception Profile for Children; their implicit associations were assessed using an Implicit Association Test. Parent and teacher ratings formed an adult-reported composite indicator of children’s competence, to which children’s self-perceptions were compared. Results: Children with ADHD overestimated their competence as compared with adult-informant reports on both explicit and implicit measures, whereas TD children tended to be accurate. Conclusion: Inflated self-perceptions in children with ADHD may exist on an implicit level outside of conscious awareness.