Purpose -This paper presents findings of a research study aimed at identifying critical sustainability factors for improved implementation of Industrialised Building Systems (IBS).It also highlights the importance of decision support, through the establishment of decision making guidelines, for sustainability deliverables in IBS development.Design/methodology/approach -A broad range of sustainability factors, as perceived by researchers and practitioners, are identified through a comprehensive literature study. A study of the survey and statistical data analysis is conducted to examine the criticality of these sustainability factors in IBS implementation.Findings -18 sustainability factors are identified as critical to IBS implementation. Their interrelationships and driving forces are explored, which leads to the development of a conceptual model to map these factors for actions or potential solutions. The work provides a sound basis towards a set of decision making guidelines for sustainable IBS implementation.Originality/value -Compared with previous studies that focus on technical or economical aspects, this study extends existing knowledge on construction prefabrication by linking all aspects of sustainability issues with the design process. It also covers industry characteristics of developing countries, as represented by Malaysia's scenarios.