Purpose: We performed a meta-analysis of randomized controlled trials (RCTs) in order to evaluate the effect of oral magnesium supplementation on lipid profile of both diabetic and non-diabetic individuals. Methods: PubMed-Medline, SCOPUS, Web of Science, and Google Scholar databases were searched (from inception to February 23, 2016) to identify RCTs evaluating the effect of magnesium on lipid concentrations. A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate the impact of potential confounders on lipid concentrations. Results: Magnesium treatment was not found to significantly affect plasma concentrations of any of the lipid indices including total cholesterol (WMD 0.03 mmol/L, 95% CI −0.11, 0.16, p = 0.671), LDL-C (WMD −0.01 mmol/L, 95% CI −0.13, 0.11, p = 0.903), HDL-C (WMD 0.03 mmol/L, 95% CI −0.003, 0.06, p = 0.076), and triglycerides concentrations (WMD −0.10 mmol/L, 95% CI −0.25, 0.04, p = 0.149). In a subgroup analysis comparing studies with and without diabetes, no difference was observed between subgroups in terms of changes in plasma total cholesterol (p = 0.924), LDL-C (p = 0.161), HDL-C (p = 0.822), and triglyceride (p = 0.162) concentrations. Conclusions: Results of the present meta-analysis indicated that magnesium supplementation showed no significant effects on the lipid profile of either diabetic or non-diabetic individuals.