Introduction: Ascariasis is the most common soil-transmitted helminths (STH) infection in children, with prevalence ranging from 6 to 60%, especially in an endemic region in Indonesia such as East Nusa Tenggara, Sumatera, and other remote areas. Ascariasis effects toward undernutrition were still unclear because there were differences between studies. This study aimed to investigate the association between Ascariasis and undernutrition in children. Methods: Six authors reviewed and analyzed eligible studies from PubMed and MEDLINE, Google Scholar, ProQuest, EBSCO-Host, and Springer Link, using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta Analyses) guidelines with Reference manager was used, and the data analyzed using Revman 5.4. Newcastle-Ottawa Scale adapted for cross-sectional studies was used to examine the publication bias. Results: This review included 15 studies and 12 studies used for meta-analyses. Pooled data indicates that Ascariasis is significantly associated with stunting (OR = 2.22, 95% CI = 1.31;3.77, p = 0.003) and underweight (OR = 1.27, 95% CI = 1.01;1.60, p = 0.04), meanwhile not significantly associated with wasted (OR = 1.11, 95% CI = 0.87;1.40, p = 0.40) of children aged 0-19 years. Conclusion: Ascariasis increases the risk of stunting and underweight among other parameters of undernutrition. Therefore, early screening, diagnosis, and intervention must be taken to prevent stunting and underweight in children.