The COVID-19 pandemic has significantly impacted individuals across all age groups, including young children under the age of 5. While children generally experience milder symptoms, the potential for post-COVID-19 co-morbidities in this age group has raised concerns among healthcare professionals and researchers. This comprehensive systematic review aims to analyze and synthesize the existing body of literature to identify, categorize, and assess post-COVID-19 co-morbidities among children aged under 5. By examining clinical manifestations, complications, and potential long-term health effects, this review provides a comprehensive understanding of the health challenges faced by this vulnerable population.