Background: Substantial evidence links loneliness to poor academic outcomes and poor employment prospects. Schools have been shown to be places that mitigate or aggravate loneliness, suggesting a need to consider how schools can better support youth experiencing loneliness. Methods: We conducted a narrative review on loneliness in childhood and adolescence to examine the literature on how loneliness changes over the school years and how it influences learning. We also examined whether there were increases in loneliness because of the COVID-19 pandemic and associated school closures, and whether schools can be places for loneliness interventions/prevention. Findings: Studies describe how loneliness becomes more prevalent during the adolescent years and why that is the case. Loneliness is associated with poor academic outcomes and poor health behaviors that impact learning or turn students away from education. Research shows that loneliness increased during the COVID-19 pandemic. Evidence suggests that creating positive social classroom environments, where teacher and classmate support are available, is crucial in combatting youth loneliness. Conclusions: Adaptations to the school climate can be made to meet the needs of all students, reducing loneliness. Investigation of the impacts of school-based loneliness prevention/intervention is crucial.