Background: Health promotion programs and interventions are designed to encourage behavioral changes in children, encouraging them to make safe and healthy life choices. This systematic review seeks to examine how social impact is measured in primary school health promotion interventions. Method: A systematic search and review process was used to identify and examine primary school health promotion interventions. The PRISMA guidelines were followed to source articles from 6 electronic databases reporting school health promotion programs or interventions in Australia, Canada, New Zealand, or the United Kingdom. Results: A total of 77 studies were located, representing 55 health promotion interventions delivered in primary school settings. Of these interventions, only 8 (15%) measured or attempted to measure social impact, whereas another 8 (15%) alluded to social impact. The predominant theories reported were social based theories (theories which examine the social influences on people, environments, and behaviors) (n = 17, 59%), with almost a third not informed by an overt health promotion framework or model (n = 34, 59%). A systematic rating system identified some level of stakeholder engagement (n = 30, 53%). Conclusions: This systematic review highlights the need for social impact measurement within health promotion to illuminate the role of school programs in delivering lasting change.