[Purpose] The purpose of this study was to examine the keywords of domestic research on music therapy for intellectual disabilities (ID) and autism spectrum disorders (ASD), and to clarify the structure by analyzing the semantic network between keywords. [Method] A total of 866 keywords of 238 types were extracted from 197 papers published on the subject of music therapy for ID and ASD in journals between 2000 and 2022. To examine past research trends, the frequency of the appearance of keywords presented in the literature was calculated. By utilizing a UCINET6 program, NetDraw was visualized after analyzing the structural properties, centrality, and ego networks. [Results] In the ID literature, keywords such as "music therapy,'' "child/adolescent with ASD,'' "child/adolescent with ID,'' "social skills,'' "group music therapy,'' "communication skills,'' and "problematic behavior'' were frequently used. In the ASD literature, keywords such as "music therapy,'' "child/adolescent with ASD,'' "child/adolescent with ID,'' "social skills,'' "group music therapy,'' "communication skills,'' and "problematic behavior'' were frequently used. The network had 68 nodes connected by 926 links, and the density was 0.2. In addition, keywords such as "music therapy,'' "child/youth with ASD,'' "child/youth with ID,'' "social skills,'' and "singing activity'' displayed high centrality. In the ego network of "child/adolescent with ID,'' "singing activity,'' "social skills,'' "music intervention,'' "attention concentration,'' and "vocabulary ability'' had high connection strength. In the "child/adolescent with ASD'' ego network, "social skills,'' "stereotyped behaviors,'' "language disorders,'' "communication skills,'' and "problematic behaviors'' had high connection strength. "Music therapy'' showed a strong connection with "child/adolescent with ASD,'' "social skills,'' "music education,'' and "music intervention.'' [Conclusion] This study identified the structure of keywords that were important in music therapy research for ID and ASD in the past, and grasped the trends of past research. Proposals for follow-up studies of comprehensive music therapy studies are also discussed.