Background Asthma is the common chronic inflammatory disease affecting children. It is usually associated with airway hyper-responsiveness. Globally, the prevalence of asthma among pediatrics population varies from 10% to 30%. Its symptoms range from chronic cough to life-threatening bronchospasm. At emergency department, all patients with acute severe asthma should initially receive oxygen, nebulized β2-agonists, nebulized anticholinergic agent, and corticosteroids. Though bronchodilators act within minutes, corticosteroids may require hours. Magnesium sulphate (MgSO 4 ) was first considered for treating asthma about 60 years ago. Several case reports were published on its usefulness in decreasing admission and endotracheal intubation. So far, evidence is conflicting to fully employ MgSO 4 for asthma management in children under five. Objective This systematic review was aimed to evaluate the effectiveness and safety of MgSO 4 in the treatment of severe acute asthmatic attacks in children. Methods A systematic and comprehensive search of literature was performed to identify controlled clinical trials conducted on IV and nebulized MgSO 4 in pediatric patients with acute asthma. Results Data generated from three randomized clinical trials were included in the final analysis. In this analysis, intravenous MgSO 4 did not improve respiratory function (RR=1.09, 95%CI: 0.81–1.45) and not safer than conventional treatment (RR=0.38, 95%CI: 0.08–1.67). Similarly, use of nebulized MgSO 4 showed no significant effect on respiratory function (RR=1.05, 95%CI: 0.68–1.64) and more tolerable (RR=0.31, 95%CI: 0.14–0.68). Conclusion Intravenous MgSO 4 may not be superior to conventional treatment in moderate to severe acute asthma among children and neither have significant adverse effects. Similarly, nebulized MgSO 4 showed no significant effect on respiratory function in moderate to severe acute asthma in children under five but it seems a safer alternative.