Background: GH deficiency (GHD) is common among childhood cancer survivors (CCSs) with history of tumors, surgery, and/or radiotherapy involving the hypothalamus-pituitary region. We aimed to evaluate the effects of GH therapy (GHT) in CCSs on adult height, risk of diabetes mellitus, abnormal lipids, metabolic syndrome, quality of life, secondary tumors, and disease recurrence. Methods: We searched multiple databases for randomized and observational studies. Pairs of reviewers independently selected studies and collected data. Random effects meta-analysis was used to pool outcomes across the studies. Results: We included 29 observational studies at moderate to high risk of bias. Sixteen studies compared CCSs on GHT with those not on GHT (512 patients, GH dose: 0.3 to 0.9 IU/kg/week). GHT was significantly associated with height gain [standard deviation score, 0.61; 95% CI, 0.08 to 1.13] and was not significantly associated with the occurrence of secondary tumors [odds ratio (OR), 1.10; 95% CI, 0.72 to 1.67] or tumor recurrence (OR, 0.57; 95% CI, 0.31 to 1.02). Thirteen studies compared CCSs on GHT with normal age- or sex-matched controls or controls with idiopathic GHD or short stature. GHT was associated with either improved or unchanged risk of diabetes, lipid profiles, and metabolic syndrome. GHT was associated with improvements in quality of life. Conclusion: CCSs treated with GHT gain height compared with the untreated controls. GHT may improve lipid profiles and quality of life and does not appear to increase the risk of diabetes or the development of secondary tumors, although close monitoring for such complications remains warranted due to uncertainty in the current evidence.