Excavations between 1954 and 1967 in the West Mouth, Niah Cave (Sarawak) uncovered the largest Neolithic cemetery in South-east Asia with over 150 burials. Subsequent work at the site in the 1970s and most recently by the Niah Caves Project (2000–2004) brought the total to 170, comprising 89 primary burials and 79 secondary burials, and two ‘multiple’ burials. The size of cemetery and the scale of the archaeological data are unprecedented in South-east Asian Neolithic archaeology and offer a unique opportunity to investigate the cemetery's origins, development, and history in detail. Analysis of the demographic structure of discrete spatial burial groups within the cemetery and their short term burial sequences are combined to interpret the history of changing burial practice in terms of different social/settlement groups using the cave as a communal place of burial. A new suite of radiocarbon dates are used to date the West Mouth Neolithic cemetery to between 1500 and 200 bc. Six phases of burial are defined and the associated transitions of ritual practices are discussed. In particular, a transition from primary to secondary burial occurred around c. 1000 bc, which subsequently intensified into the practice of cremation. This process was likely associated/fuelled by an intensification of economic activity to support more elaborate secondary burial funerals. Two further cycles of primary and secondary burial followed, before the main cemetery ceased c. 200 bc. A Post-Neolithic phase of possibly 14 burials (five primary flexed burials and nine secondary burials) is proposed to follow, which while continuing aspects of Neolithic mortuary behaviour, is considered on isotopic data to represent a group of hunter-gatherers living in a closed-canopy environment