This study explored the impacts of enactment and motor imagery on working memory for instructions in children with autism spectrum disorder (ASD), children with intellectual disability (ID) and typically developing (TD) children. The participants were asked to hear (hearing condition), imagine enacting (motor imagery condition) and actually enact (enactment condition) instruction sequences and then recall them orally. Compared with the hearing condition, all groups performed better in the enactment condition, with the greatest advantage exhibited by the TD group; however, only the TD children performed better in the motor imagery condition. In summary, enactment has a weaker facilitating effect on ASD children and ID children than on TD children, and motor imagery is ineffective in the former two groups.