The few reports on the language skills of children with attention-deficit/hyperactivity disorder (ADHD) offer conflicting evidence on whether they face significant challenges, and if so, whether these challenges are present in all aspects of language. Here, we investigated a sample of Greek-speaking children with ADHD (n = 29) using a structural language (vocabulary, grammar) and a pragmatic language assessment. To ascertain the extent of strengths and weaknesses, we compared the performance of children with ADHD to typically developing (TD) peers (n = 29) and also to children with developmental language disorder (DLD; n = 25), who face challenges particularly in structural language. As regards structural language, ADHD children performed significantly lower than their TD peers but significantly higher than the DLD group. In pragmatics, ADHD children performed numerically lower than any other group, but differences did not reach statistical significance. Children with ADHD face difficulties with language skills and especially with structural language. Sophisticated linguistic assessment is crucial, as it facilitates the identification of children with different challenges by measuring performances on distinct components. Language difficulties in ADHD should not be overlooked but must be evaluated thoroughly for more effective intervention planning.