Mass customization as a strategy has been utilised successfully in the manufacturing industry meeting customers’ idiosyncratic needs in a cost-efficient way. The productivity of the Danish manufacturing industry has increased six times over the last 50 years, whereas the Danish construction industry has only doubled. Mass customization has not been extensively explored in the construction industry; therefore, the theoretical background is currently limited. Nevertheless, utilization of mass customization as a strategy might have potentials in the construction industry. This research is a multi-case study of 11 companies in the construction industry focusing on how the cases apply the three fundamental capabilities of mass customization 1) solution space development, 2) choice navigation and 3) robust process design, and how their improvement initiatives effect performance, and how the cases plan to develop the three fundamental capabilities of mass customization. The outset is an analysis of project phases and critical success factors characterizing the cases followed by an analysis of how the cases apply and plan to develop the nine tools and approaches supporting the development of the three fundamental capabilities of mass customization. The data are collected through interview as a two-way communicative approach providing holistic and in-depth explanations of the 18 variables of the analysis. The results are that all 11 cases aim at increasing all nine tools and approaches, which strengthen the utilization of the three fundamental capabilities of mass customization in the sense of improving the productivity. This research put forward a definition of mass customization intending to make the concept more visible and accessible for the construction industry.