Pollen, phytolith and charcoal records from the archaeological wetland site of Kuk Swamp, Wahgi Valley, Papua New Guinea spanning the period from <20,000 to 270 cal BP are compiled to reconstruct past vegetation and plant exploitation during the earliest to late phases of agricultural development. Samples collected from exposed stratigraphic sections associated with archaeological excavations enable detailed reconstructions of local vegetation and fire histories that can be directly linked to archaeological evidence for agricultural activity. The record of past environmental change is constructed through detailed chronological control and stratigraphic correlation across the swamp, revealing evidence of early Holocene vegetation disturbance including short-term, patchy forest loss and burning considered indicative of plant exploitation. It is not until the mid-Holocene (after 7000 cal BP) that persistent and widespread forest loss occurs, with burning and the transplanting of Musa banana into an open grassland environment, which is contemporary with local archaeological features representing cultivation practices. Multi-proxy palaeoecological evidence at Kuk provides a robust vegetation history and land use chronology for the Upper Wahgi Valley for the late Pleistocene and Holocene, including the emergence of an agricultural landscape by 7000 cal BP. Subsequent agricultural developments in the highlands of New Guinea can be seen as a series of continuing indigenous innovations in agricultural technology in the face of increased land degradation, climate change and external influences.