Background and AimsEarly identification and treatment of hypertension could lower the risk of cardiovascular diseases; which share the largest proportion of death. The findings of previous studies done in Ethiopia on undiagnosed hypertension were inconsistent. Therefore, this systematic review and meta‐analysis aimed to assess the prevalence and associated factors of undiagnosed hypertension among adults in Ethiopia.MethodsA protocol with registration number CRD42023395445 was registered to Prospective Register of Systematic Reviews (PROSPERO). A comprehensive search of observational studies done on undiagnosed hypertension was identified in PubMed, Google Scholar, Cochrane Library, Hinari databases, and other sources available until January 10, 2023. The quality of the identified studies using the set criteria and necessary data was extracted and exported to R version 4.2.3 and STATA version 15.0 for analysis. The pooled prevalence of undiagnosed hypertension and its associated factors were identified. The risk of bias was evaluated using a funnel plot and Egger's test. The findings were presented using tables, figures, and statements. This study was not funded by any organization.ResultsEleven studies having 6132 participants were included in the analysis. The pooled prevalence of undiagnosed hypertension was 21% (95% confidence interval [CI]: 16–27). In subanalysis, according to the American Heart Association ( ≥ 130/80 mmHg), the pooled prevalence was 29% (95% CI: 18–40). However, according to the International Society of Hypertension ( ≥ 140/90), the pooled prevalence was 16% (95% CI: 13–20).Sex (AOR = 2.49, 1.48–3.49), age ≥55 years (AOR = 2.68, 1.16–4.21), alcohol drinking (AOR = 2.68, 1.68–3.69), body mass index ≥25 kg/m2 (AOR = 2.62, 1.77–3.48), and high triglyceride levels (AOR = 1.87, 1.22–2.51) were significantly associated with it.ConclusionIn Ethiopia, about one in five adults ≥ 18 years has undiagnosed hypertension; therefore raising public awareness for medical checkups, early hypertension detection, and treatment is suggested. However, these findings cannot be generalized to pediatrics.