Background: Lower mortality among migrants than in the general population has been found in many, but not in all, previous studies. The mortality of migrants has not been studied in Finland, which has a relatively small and recent migrant population. Methods: People who were born abroad and whose mother tongue is not Finnish were identified from the Finnish Central Population Register (n = 185 605). A Finnish-born control matched by age, sex and place of residence was identified for each case (n = 185 605). Information about deaths was collected from the Finnish Causes of Death Register. Cox proportional hazards model was used for assessing the association between migrant status and death in 2011–13. Results: The mortality risk was found to be significantly lower for migrants than for Finnish controls (adjusted hazard ratio 0.77, 95% CI 0.72–0.84), both for migrant men (aHR 0.80, 95% CI 0.73–0.89) and women (aHR 0.78, 95% CI 0.70–0.88). The difference was statistically significant only among people who were not married and among people who were not in employment. There was variation by country of birth, but no migrant group had higher mortality than Finnish controls. No differences in mortality were found by duration of residence in Finland. The higher mortality of Finnish controls was largely explained by alcohol-related conditions and external causes of death. Conclusions: The mortality risk of migrants is lower than of people who were born in Finland. Possible explanations include selection and differences in substance use and other health behaviour.