In this chapter, we approach mergers and acquisitions (M&As) from an engagement lens. Reflecting the assumptions of positive organizational scholarship (Cameron et al. 2003; Cameron and Spreitzer 2012), engagement offers a positive take on employee presence and involvement at work (Kahn 1990, Rothbard and Patil 2012). Such a take differs markedly from the reality of many a merger or acquisition, where negative emotionality prevails (Napier 1989; Cartwright and Cooper 1990; Marks and Vansteenskiste 2008). We begin by considering 1) the case for engagement and 2) the performance consequences of an engaged workforce. We then 3) review the theoretical perspectives through which engagement has been approached, discussing their relevance to M&As. This leads us to 4) propose a typology of engagement scenarios in times of M&A, be it by nurturing individual action or by means of organizational support. In light of the many audiences impacting M&As, we finish the chapter with 5) an overview of how differing audiences’ engagement dynamics differ in pre-and post-transaction eras. In so doing, our chapter contributes to theorizing on M&As by introducing an engagement lens to employee reactions and involvement during M&As. We also contribute to theorizing on engagement by illustrating the need for engaged employees not only in seemingly static, i.e. normal, work contexts, but also in times of major changes, such as mergers or acquisitions. We argue that, given the radical change in ownership and psychological contract that they represent, M&As offer an arena, wherein the engagement of employees is particularly needed.