Background <p>Autistic traits (ATs) are prevalent and clinically significant among children with Attention Deficit/Hyperactivity Disorder (ADHD); however, their specific behavioral correlates have not been fully characterized. This cross-sectional study investigated the presence of ATs and their relationship with behavioral profiles within this population.</p> Methods <p>A total of 154 children were enrolled, including 48 healthy controls (HCs), 69 children with ADHD, and 37 children with comorbid ADHD and Autism spectrum disorder (ASD). The Autism Spectrum Screening Questionnaire (ASSQ) and the Child Behavior Checklist (CBCL-ASD), composed of Withdrawn, Thought Problems, and Social Problems subscales, were used to assess ASD symptoms and explore the structure of ATs. ATs were defined as a total score of ASSQ ≥ 12, leading to the subdivision of the ADHD group into ADHD without ATs (ADHD-ATs, <i>n</i> = 40) and ADHD with ATs (ADHD + ATs, <i>n</i> = 29). To characterize the non-ASD behavioral features associated with ATs, behavioral differences across HCs, ADHD-ATs, ADHD + ATs, and ADHD + ASD groups were compared using CBCL non-ASD scales.</p> Results <p>1. ATs in ADHD: Compared to HCs, the ADHD group showed significantly higher scores on all ASSQ and CBCL-ASD measures except the ASSQ communication problems subscale (all <i>P</i> &lt; 0.05). However, their scores were lower than those in the ADHD + ASD group (all <i>P</i> &lt; 0.05). When further divided by ATs, the ADHD + ATs subgroup exhibited widespread ASD-related impairments. Their ASSQ scores and CBCL-ASD social problems scores exceeded those of both ADHD-ATs and HCs (all <i>P</i> &lt; 0.05), and were comparable to the ADHD + ASD group. 2. Non-ASD Behaviors in ADHD + ATs subgroup: Apart from anxiety/depression, the ADHD + ATs group scored higher than both ADHD-ATs and HCs on all CBCL-non-ASD scales, and exceeded ADHD + ASD in aggressive behavior and rule-breaking (all <i>P</i> &lt; 0.05). Multiple linear regression showed that aggressive behavior was predicted by social-interaction, withdrawn and thought problems scores; rule-breaking was predicted by communication problems scores, withdrawn and thought problems; attention problems was predicted by all CBCL-ASD scales; somatic complaints was predicted by social-interaction and thought problems.</p> Conclusions <p>ATs may represent a clinically characterized subgroup within ADHD, characterized by global impairments across all core ASD symptom domains, alongside elevated non-ASD behavioral problems, particularly in externalizing behaviors. Notably, specific ASD symptom profiles differentially predict distinct patterns of non-ASD behaviors. Exploring the ATs subgroup can help elucidate the heterogeneity and complexity of ADHD, thereby contributing to precision treatment for the disorder.</p> Clinical trial number <p>Not applicable.</p>