The sociomaterial lens within IS research holds that agency should not be considered as a property solely of humans, or of technology, but instead arises from an emergent interaction between the two. This, emergent, account of agency deepens our understanding of unfolding IS practice, but its largely cognitive orientation remains naïve towards affectively-sensed motivations that also form part of this interaction. By implication, a sociomaterial perspective lacking an affective dimension offers an incomplete conceptualisation of information systems. In response, an affectively-informed negative ontology encourages IS researchers to extend their focus beyond the visible, to encompass how actors’ receptiveness towards material objects (discourses, technologies) is shaped by deep, affectively-derived motivations of which they are not focally aware, but which nonetheless acquire agency in contributing to a sociomaterial outcome. A central argument, and illustrative empirical vignette, demonstrate how the concepts of sociomateriality, affect, and negative ontology combine to offer researchers an enhanced understanding of relational agency. A discussion follows, exploring some initial ontological, epistemological and methodological implications of an affectively-informed negative ontology for IS research.