There has been limited research on the acquisition of grade-aligned science skills for students with moderate intellectual disability, with even more restriction on academic skills in inclusive settings. This study examined the effects of peer-mediated time-delay instruction to teach inquiry science and use of a knowledge chart to students with moderate intellectual disability in an inclusive setting. Six general education peers implemented an embedded constant time-delay procedure during three science units with 5 students with moderate intellectual disability. All 5 students increased the number of correct science responses across all science units. Three students required additional support by the special education teacher to reach mastery. In addition, all 6 peers were able to implement the intervention with high fidelity, while maintaining science grades at preintervention levels. High levels of social validity were reported. (Contains 1 table and 6 figures.)