Dialogic reading (DR) is an interactive reading approach that enhances the language development of children. This study aims to extend DR to the shared reading context involving children with attention-deficit-hyperactivity disorder (ADHD) and their older siblings and to examine the effects of DR with parents/siblings on the language development of Chinese children with ADHD. This study included 850 Chinese kindergarteners with ADHD and their parents/older siblings. These children were pretested on their Chinese receptive vocabulary, expressive vocabulary, character reading, listening comprehension, and reading interest and were randomly assigned to four groups, namely, dialogic reading with parents (PR-DR), dialogic reading with siblings (SR-DR), parent reading control (PR-C), and sibling reading control (SR-C). After a 12-week intervention period, they were posttested on the same measures. Results show that both DR with parents and siblings effectively enhanced language skills and reading interest in children with ADHD. In addition, those children who read with their older siblings demonstrated greater improvements in their expressive vocabulary, character reading skills, morphological awareness, phonological awareness, and reading interest yet achieved a smaller growth in their listening comprehension compared with those who read with their parents. These findings showed the positive effects of DR on the language development of children with ADHD and highlight the importance of involving siblings in home literacy activities to facilitate the language development of these children.