Students' attitudes, intentions and behaviours towards their peers with disabilities are important to their mutual co-existence and development. The aim of this study was to investigate a) whether students' attitudes and intentions towards their schoolmates with disabilities are related to their general and modified behavior in mainstream physical education classes, and b) if the former variables could serve as predictors of the latter. The participants, 172 children without disabilities (M[subscript age]=11.15, SD=0.70), completed the revised version of the Planned Behavior Theory questionnaire (PBT) and the Children's' Attitudes towards Inclusion in Physical Education-Revised questionnaire (CAIPE-R). Although results revealed several correlations among the variables under study, only general attitudes accounted for both general and modified behavior, and attitudes for modified behavior. These findings could assist in educating students to develop and perform appropriate behaviours towards their peers in order to facilitate their co-existence, and their mutual development and learning.