Background: In recent years, there has been a global effort to support the inclusion of students with intellectual disabilities (ID) in schools and classrooms. China in particular has recently enacted laws that provide for inclusive educational opportunities for students with ID. There are many barriers, however, to successfully including students with ID in regular education schools and classrooms, one of which is negative attitudes. Over the past decade, much research has focused on documenting the attitudes of the adult public; however, adults only represent one segment of society as it is youth who play a critical role in the successful inclusion and acceptance of students with ID in schools and classrooms. The aim of this study was to replicate a previous study of middle school-aged youths' attitudes towards the inclusion of peers with ID conducted with youth in the USA with similar aged youth in China. Methods: A survey was conducted with a random sample of 4059 middle school-aged youth in China on their attitudes towards students with ID. Students' attitudes were measured in terms of their perceptions of the capabilities of students with ID, their beliefs about and expectations regarding the inclusion of students with ID and their willingness to interact with students with ID both in and out of school. Results: The findings indicated that youth in China (1) perceive students with ID as moderately, rather than mildly, impaired; (2) believe that students with ID can not participate in their academic classes; (3) view inclusion as having both positive and negative effects on them personally; and (4) do not want to interact with a peer with ID in school, particularly on academic tasks. Structural equation modelling showed that youths' perceptions of the competence of students with ID significantly influenced their willingness to interact with these students and their support of inclusion. Conclusions: The findings replicated previous research conducted with middle school-aged youth in the USA and are discussed from a cultural perspective and in terms of the current special education policies and practices in China.