An estimated 190 million people are now living outside their countries of birth or citizenship, and the rate of this migration is expected to remain high. The resulting growing cultural and ethnic diversity in societies adds specific challenges to the requirement of delivering public services such as health care to consumers. Globally, about half of the migrant population are women. Migrants’ outcomes of pregnancy are known to be poor, showing significant disparities when compared with those of native populations. Although these disparities have been noted, knowledge is limited regarding the availability and accessibility of healthcare services, as well as the acceptability of maternity care for women with experiences of free and forced migration. Healthcare research in general, and maternity care research specifically, have often neglected this population. This paper examines the existing international guidelines intended to address inequities in health outcomes, policies which have been introduced at national levels, and the widely used concepts of ‘patient-centred’ and ‘woman-centred’ health services. The ideals implicit in those guidelines and concepts are contrasted with the available evidence of many overseas nationals’ experiences with healthcare provisions in general, and maternity care in particular. This is followed by reflections on deficiencies in current studies and on those methodological problems which make research on maternity care for migrant women particularly challenging. The conclusion considers the appropriateness and relevance of guidelines currently promoting equity in maternity care and suggests a future agenda for priority research.