This article contributes to and develops the previous literature on excess resources (“slack”) in nonprofit organizations through a conceptual analysis of the implications that the organizational distinctiveness of nonprofits carries for our understanding of slack in these organizations. We argue that this distinctiveness has important implications for (i) the threshold level at which resources become slack in nonprofit organizations; (ii) the type of resources that can be considered to constitute slack in nonprofits; and (iii) the different categories of slack to which nonprofit researchers should pay special attention. In particular, we propose an additional slack category to expand the classical typology: tappable slack. Importantly, we also suggest that in order to be relevant and useful also in the nonprofit context, the concept of organizational slack needs to be analytically linked to the mission of the organization. As an empirical illustration of these theoretical points, we discuss the resource use of the Church of Sweden and its parishes during the European refugee reception effort in 2015–2016.