PURPOSE: Most people with epilepsy (PWE) in low-income countries are not treated. We identified risk factors for the epilepsy treatment gap in rural Tanzania. METHODS: We identified adult PWE in a community-based prevalence study. Factors associated with failure to access or default from medical care were identified using logistic regression modelling. RESULTS: A total of 291 PWE were included, of whom 253 (86.9%) had presented to medical services. Failure to present was positively associated with using alcohol (odds ratio (OR) 4.20; 95% confidence interval (CI) 1.63 to 10.82) or attending traditional healers (OR 2.62; CI 1.00 to 6.83) and inversely associated with having completed primary education (OR 0.33; CI 0.11 to 0.96). Default from treatment was associated with being male (OR 3.35; CI 1.39 to 8.09), having a seizure-related injury (OR 2.64; CI 1.12 to 6.19), believing in a supernatural cause for epilepsy (OR 5.44; CI 1.48 to 19.94) or having no expressed knowledge of cause (OR 5.29; CI 1.60 to 17.52). Cases less likely to default had a duration of epilepsy greater than 10 years (OR 0.28; CI 0.09 to 0.90) or had previously received a seizure-related diagnosis (OR 0.25; CI 0.09 to 0.65). Of all 291 PWE included, 118 denied taking AEDs; the epilepsy treatment gap in this population was therefore 40.5% (95% CI 34.9 to 46.2). CONCLUSION: Interventions to improve access to education and to support formal diagnoses may promote access to, and retention under, medical care for PWE in rural Tanzania and in other low-income countries.