The proliferation of collaboration platforms in organisations has benefits for knowledge workers in terms of access to knowledge and social resources. However, negative effects, specifically collaborative overload, have only recently been acknowledged and are still rarely considered by companies. Collaborative overload is a multi-faceted construct, which covers downsides, unintended or side-effects of collaboration platforms and their organisational use. To introduce and explore what we believe is an important phenomenon, we conducted a narrative literature review to contextualise collaborative overload and to provide a structured account of underlying root causes. Based on this, we propose an agenda for future research and derive an initial research framework to clarify and delineate collaborative overload. With this twofold contribution, we aim to provide a frame of reference for the discourse about this important syndrome of modern workplaces