BackgroundHypertension is a major public health problem, resulting in 10 million deaths annually. Undiagnosed hypertension affects more people than ever before. It is more likely to be linked to severe hypertension, which can lead to stroke, cardiovascular disease, and ischemic heart disease. Thus, this systematic review and meta-analysis aimed to synthesize the prevalence of undiagnosed hypertension and its associated factors in Ethiopia.MethodsDatabases, such as Medline/PubMed, Google Scholar, Science Direct, AJOL, and the Cochrane Library, were systematically searched to find potential studies published until December 2022. A Microsoft Excel spreadsheet was used to enter the extracted data. The pooled prevalence of undiagnosed hypertension and its associated factors was estimated using a random effect model. I2statistics and the Cochrane Q-test were used to assess statistical heterogeneity across the studies. Begg’s and Egger’s tests were performed to identify possible publication bias.ResultsA total of ten articles with 5,782 study participants were included in this meta-analysis. In the random effects model, the pooled prevalence of undiagnosed hypertension was 18.26% (95% CI = 14.94–21.58). Being older (OR = 3.8, 95% CI = 2.56, 5.66), having a body mass index > 25 kg/m2 (OR = 2.71, 95% CI = 2.1, 3.53), having a family history of hypertension (OR = 2.22, 95% CI = 1.47, 3.36), and having DM comorbidity (OR = 2.44, 95% CI = 1.38, 4.32) were significantly associated with undiagnosed hypertension.ConclusionIn this meta-analysis, the pooled prevalence of undiagnosed hypertension was found to be high in Ethiopia. Being older, having a BMI > 25 kg/m2, having a family history of hypertension, and having DM comorbidity were found to be risk factors for undiagnosed hypertension.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12872-023-03300-0.