Background and Objective: Olanzapine (OLZ) containing regimens are approved in adults for chemotherapy-induced nausea and vomiting (CINV) receiving highly emetogenic chemotherapy (HEC) or moderately emetogenic chemotherapy (MEC), and the same has not been approved in the pediatric population. In order to generate data regarding the efficacy and safety of OLZ as an adjunct to the standard of care (SoC) for CINV in pediatric patients receiving HEC/MEC, the review authors performed this systematic review and meta-analysis. Methods: A systematic literature search was performed through the databases Cochrane Library, Pub Med, and clinicaltrials.gov, from inception to September 2023, using keywords: “chemotherapy” and “olanzapine,” “nausea” and “vomiting.” Randomized clinical trials published in English that analyzed the efficacy and safety of olanzapine as an adjunct to SoC were included. The essential outcomes included in this study were the proportion of patients with no emesis in the acute and delayed phase, patients with no nausea in the acute and delayed phase, the proportion of patients requiring rescue medication, and the proportion of patients with reduced CNS arousal. Results: In the OLZ group, a greater number of patients had no emesis both in the acute and delayed phase (RR = 1.22; 95% CI = 1.09-1.37; P = .0004); and (RR = 1.23; 95% CI = 0.92-1.63; P = .16) respectively. Similarly, a higher number of patients showed no nausea both in the acute and delayed phase (RR = 1.08; 95% CI = 0.78-1.48; P = .66) and (RR = 1.12; 95% CI = 0.79-1.61; P = .52) respectively. The use of rescue medication was significantly less in the OLZ group (RR = 0.62; 95% CI = 0.42-0.91; P = .01). More patients experienced reduced CNS arousal in the OLZ group (RR = 2.97; 95% CI = 2.02-4.38; P < .0001). Conclusions: Olanzapine as an adjunct to the SoC may be effective in acute emesis, which may also reduce the use of rescue medication. Reduced CNS alertness was the significant adverse effect observed. For other endpoints, more studies are required to substantiate its role in CINV.