Industrialised Building System (IBS) is a construction process that uses standardised building components mass produced in a factory or on site, then transported and assembled into a structure using appropriate machinery and equipment with minimal workers on site with proper planning and integration. IBS is the term used to represent the prefabrication concept in Malaysian construction industry. IBS contributes to sustainability, improves site safety, quality and productivity in the built environment. Since the move towards industrialisation in the construction industry is a global phenomenon, the definitions, classifications, characteristics and concepts of IBS needs to evolve and in line with the global understanding. The main objective of this paper is to study the way forward for IBS (adopting sustainability, degree of industrialisation and modular construction) and revisit the current definitions, classifications, characteristics and concepts in IBS based on comprehensive reviews of previous researches with an explanatory method. Better understanding on the fundamentals and future improvement of IBS will encourage construction industry players to adopt IBS and increase the awareness on IBS.