BACKGROUND: Undocumented migrants, in particular pregnant women and their newborns, constitute a particularly vulnerable group of migrants. The aim of this study was to systematically review the academic literature on the use and outcomes of maternal and child healthcare by undocumented migrants in the European Union (EU) and European Free Trade Association (EFTA) countries. METHODS: The databases, MEDLINE, Embase, CINAHL Plus, Global Health and Popline were searched for the period 2007 to 2017. Two independent reviewers judged the eligibility of studies. The final number of included studies was 33. RESULTS: The results of quantitative, qualitative and mixed methods studies were analysed separately due to their differences in study design, sample size and quality. Overall, the quantitative studies found that undocumented women underutilised essential maternal and child healthcare services, and experienced worse health outcomes. Qualitative studies supported these results, indicating that undocumented migrants were hesitant to use services due to a lack of knowledge and fear of deportation. Studies included in the review covered 10 of 32 EU or EFTA countries, making a European comparison impossible. CONCLUSIONS: Despite major methodological differences between included studies, the results of this review indicate that the status of undocumented migrants exacerbates known health risks and hampers service use.