The potential for behaviourally challenged students to negatively impact typically developing students is a concern shared by many parents and teachers. However, deviant peer influence during workgroup activities has not been thoroughly investigated through systematic observation of deviant interactions. This study compares sequences of deviant behaviours and peer responses recorded during cooperative activities. Seventy fifth-grade elementary school students were observed in three specific contexts, homogeneous EBD workgroups, homogeneous regular workgroups and inclusive workgroups. Findings reveal a greater prevalence of verbal aggressions and more explosive exchanges in EBD workgroups. In groups consisting solely of typically developing students, intentionally ignoring disruptive teammates proved to be effective in stopping deviant behaviours. Finally, it was in inclusive workgroups that observed deviant interactions sequences were the longest. These findings are discussed in relation with the role of group composition and workgroup training in fostering effective cooperative learning environments.