Vaccination is an effective strategy to prevent tetanus, and in Portugal this service is provided free of charge. Despite this, immigrants reported lower tetanus vaccination coverage than did Portuguese natives. The objective of this study was to identify sociodemographic, migration-related, and access-to-care factors associated with tetanus vaccination coverage among adult immigrants, using data from the Portuguese National Health Survey 2014. For the sample of 1277 immigrants aged ≥18 years, we estimated self-reported tetanus vaccination within the preceding 10 years and its determinants using complex samples logistic regression. The overall self-reported tetanus vaccination coverage was 79.5% (95% CI: 75.8-82.8). Age (adjusted odd ratio (aOR) per 1 year age increase = 0.97, 95% CI: 0.95-0.99), higher household income per adult (aOR = 0.42, 95% CI: 0.19-0.96), having Portuguese citizenship (aOR = 2.30, 95% CI: 1.25-4.24), having private health insurance (aOR = 1.99, 95% CI: 1.06-3.71), and contact with family/general physician in the last 12 months (aOR = 1.59, 95% CI: 1.01-2.51) were associated with self-reported tetanus vaccination coverage among adult immigrants. We also found significant disparities in coverage between regions of residence. This study identified several determinants associated with self-reported tetanus vaccination coverage among adult immigrants in Portugal. These findings may help policymakers to design specific interventions to increase tetanus vaccination coverage among this population.