BACKGROUND: Familial hypercholesterolemia (FH) is a prevalent and potentially fatal illness that causes a substantial elevation in low-density lipoprotein cholesterol (LDL-C). OBJECTIVE: The aim of this study was to investigate the effects of monoclonal antibodies alirocumab and evolocumab on LDL-C and other lipid parameters, as well as their safety in familial hypercholesterolemia patients. METHODS: A comprehensive search was done on PubMed/MEDLINE, EMBASE, Web of Science (WOS/ ISI), Scopus, ClinicalTrials (www. CLINICALTRIALS: gov), and conferences/ congress research papers. Random effect models were used to calculate mean differences (%) and risk ratios (RRs), and confidence intervals (95%). RESULTS: Ten studies (n=1489 patients) were included in this study. PCSK9 inhibitors decreased the levels of LDL-C by -49.59% (95%CI -55.5%, -43.67%) as compared to placebo. They also didn't alter the Treatment-Emergent Adverse Event (TEAE) and neuronal events by RR 0.92 (0.75, 1.13) and 1.31 (0.66, 2.59), respectively. PCSK9 inhibitors were effective and safe in treating patients with FH. CONCLUSION: There was high-quality evidence showing that monoclonal antibodies (alirocumab & evolocumab) lower LDL-C (GRADE: high), lipoprotein (a) (GRADE: High), triglycerides (TG) (GRADE: High), total cholesterol (GRADE: High), non-high-density lipoprotein cholesterol (non- HDL-C) (GRADE: Moderate), and apolipoprotein B (GRADE: High), and increase the HDL-C (GRADE: High) as well as apolipoprotein A1 (GRADE: High). Comparing PCSK9 inhibitors against placebo, neither TEAE (GRADE: high) nor neuronal events (GRADE: moderate) were changed.