Social interaction difficulties are amongst the most prevalent and pervasive adverse outcomes for children and adolescents with ADHD. Problem-solving strategies are impaired in affected individuals, according to the literature. This study aimed to investigate the social problem-solving skills of children and adolescents with and without ADHD, using objective quantitative measures provided by the Interpersonal Negotiation Strategies Interview (INSI). Since verbal communication skills and working memory may be impaired in ADHD, we investigated their contribution to the performance. Forty-three children and adolescents with ADHD and 27 clinical controls with clinical diagnoses other than ADHD completed the INSI along with measures of verbal communication skills (Verbal Comprehension Index [VCI]): Similarities, Vocabulary and Comprehension subtests from the Wechsler Battery, visual (Corsi Blocks) and verbal (Digit Span) working memory tasks. Groups performed similarly on measures of intellectual functioning, working memory, and verbal communication. For the entire sample, VCI scores were positively correlated with INSI performance scores. The ADHD group performed worse on the INSI than the clinical control group. Linear regression analysis showed that inattention and hyperactivity/impulsivity levels and Similarities predicted INSI's performance. Our findings indicate that interpersonal negotiation difficulties in ADHD are related to DSM-5 defining symptoms of the disorder.