Teaching science education has remained limited for students with intellectual and developmental disabilities (IDD), which, in turn, has resulted in an ongoing discrepancy between these students and their typically developing peers for decades. Although there is a growing body of research in effective teaching approaches aimed at overcoming this discrepancy, there is still a need to identify evidence-based practices for addressing this academic core content. The purpose of this meta-analysis was to (a) find out the skills taught in science education to students with IDD, (b) define the characteristics of instructional approaches or adaptations of instructional approaches used to teach science content and practices, (c) conduct visual and effect size analysis of science education studies meeting the Council for Exceptional Children (CEC) quality indicators (QIs; Cook et al., 2015), and (d) determine whether there are differences in effect sizes of science education studies meeting CEC QIs based on participant and intervention characteristics. Of 27 studies reviewed, 18 studies met all the CEC QIs. A meta-analysis of these 18 studies resulted in an overall medium effect size of 0.82 CI95 (0.76, 0.87). While all the moderator variables showed a medium effect size in participant characteristics, intervention characteristics showed differences in effect sizes for comprehension-based learning and peer and researcher-implemented interventions.