BACKGROUND: Despite the supplementation of iron-folic acid is the recommended strategy during the antenatal period; iron deficiency anemia is the commonest hematologic complication during pregnancy. Therefore, this systematic review and meta-analysis aimed to assess the level of adherence to iron-folic acid supplementation and its associated factors among pregnant women in Ethiopia. METHODS: Systematic review and meta-analysis guideline was followed for this study. Different online databases were used for the review: PubMed, HINARI, EMBASE, Google Scholar and African Journals Online. Different searching terms were applied based on the adapted PICO principles to achieve and access all the essential articles. The data were entered and analyzed using Microsoft Excel and Stata 11 software respectively. RESULTS: Fifteen studies were included in this systematic review and meta-analysis with a total of 5808 pregnant women. The overall pooled prevalence of adherence to iron-folic acid supplementation among pregnant women in Ethiopia was 41.38% (95% CI: 33.09, 49.67). Having secondary and above educational status of the women (AOR:2.68,95%CI:1.25, 5.74), having an early registration of antenatal care follow-up (≤16 weeks) (AOR:2.54,95%CI:1.99, 3.24), having anemia complication during current pregnancy (AOR:3.01,95%CI:1.88, 4.81), having good knowledge of iron-folic acid supplementation (AOR: 2.96, 95%CI:1.76, 4.99), having four times or more antenatal care follow up (AOR:3.66, 95%CI:2.81, 4.77), getting health education about benefit of iron and folic acid (AOR:2.62,95%CI:1.46,4.72), and having good knowledge about anemia (AOR:2.99,95%CI:2.32, 3.85) were associated risk factors for adherence to iron-folic acid supplementation. CONCLUSION: The overall pooled prevalence adherence of IFAS among pregnant women was lower than the WHO recommendations. Educational status, early registration of ANC, anemia in the current pregnancy, good knowledge of IFAS, number of ANC visits, good knowledge of anemia and receiving health education about the benefit of IFAS were factors associated with the adherence of IFAS among pregnant women in Ethiopia. This finding is important to design strategic policies and to prevent anemia and congenital anomaly resulted from inadequate intake of iron and folic acid.