It has been claimed that systemic change encompassing various levels and multiple actors in society is needed to solve the current sustainability crisis (Glasbergen, 2010). To achieve this, business organizations with their stakeholders, among other societal actors, need to be involved to enhance sustainable development in the society (Dentoni et al., 2017). Sustainable development can be defined as the "development that meets the needs of the present without compromising the ability of future generations to meet their own needs" (World Commission on Environment and Development, 1987, p. 8). Previous research has demonstrated that the current business practices have contributed to creating sustainability challenges, such as climate change, poverty and resource deficiencies (Pattberg & Widerberg, 2016); nevertheless, firms also control crucial capabilities and resources needed to solve sustainability problems (Loorbach et al., 2010;Rhodes et al., 2014). However, research on how firms can engage with their stakeholders to contribute to societal change in the direction of sustainability is scarce.Using stakeholder theory (Freeman, 1984) as a starting point, in this chapter we examine the key assumptions and characteristics of stakeholder engagement in sustainability transitions and how such engagement may further these transitions. For this purpose, we focus on firmstakeholder relationships and build on relational stakeholder theory (Freeman et al., 2010;Kujala & Sachs, 2019;. Stakeholders are defined as individuals or groups that can affect or be affected by the achievement of a firm's objectives (Freeman, 1984).In this chapter, stakeholder engagement refers to diverse stakeholder relationships and multiple stakeholder interactions. Stakeholder engagement, which embodies the ideas of stakeholder theory, can be defined as organizational practices aimed at involving stakeholders in a positive and collaborative manner in the activities of a firm (Greenwood, 2007). It involves stakeholder identification, relationship-building among stakeholders, the alignment of stakeholder interests, internal and external communication, stakeholder dialogue and learning with and from stakeholders (Kujala & Sachs, 2019;O'Riordan & Fairbrass, 2014;Smith, 2017). It has been acknowledged as a useful practice for jointly addressing challenging issues and creating value (Aakhus & Bzdak, 2015;Freeman et al., 2017).By sustainability transitions, we refer to "long-term, multi-dimensional and fundamental transformations of large socio-technical systems towards more sustainable modes of production and consumption" (Markard et al., 2012, p. 956). Transformations of socio-technical systems entail changes in technological, material, organizational, institutional, political, economic and socio-cultural dimensions (Markard et al., 2012). Thus, sustainability transitions require collaboration across various sectors if new ways of doing, thinking and organizing are