This chapter reviews current research on the role of multinational corporations (MNCs) as employment relations (ER) actors. Far from contextualising MNCs within institutional vacuums, recent contributions have visualised these significant employers as essential players in a more complex and multilevel ER sphere. The chapter analyses how power dynamics outside and within MNCs shape their behaviour and interplay with other actors. First, MNCs are studied inasmuch as they act as rule-takers, conforming to legal, cultural and social requirements in different nation states as opposed to bypassing and circumventing institutional arrangements. Examples of different degrees of local adaptation on ER practices are given as well as some examples of ‘institutional layering’ such as double-breasting and non-unionism. Second, MNCs are also conceptualised as rule-makers, focusing on their capacity to dictate changes in institutional settings, be it nationally or internationally. The emphasis, then, is placed on the socio-political pressures MNCs can apply on governments and other ER actors as well as on the institutional plasticity MNCs are able to instigate. Sources of power at macro and micro levels are also reviewed.