New radiocarbon dates for the Neolithic settlement at Pool on Sanday, Orkney, are interpreted in a formal chronological framework. Phases 2.2 and 2.3, during which flat-based Grooved Ware pottery with incised decoration developed, have been modelled as probably dating to between the 31st and 28th centuries cal bc. There followed a hiatus of a century or so, before the resumption of occupation in Phase 3, which has a different Grooved Ware style featuring the use of applied decoration. This has been modelled as probably dating from the 26th to the 24th centuries cal bc. The implications of these results are discussed for the emergence and development of Grooved Ware, and for the trajectory of settlement and monumentality on Sanday.