PurposeSustainability in the built environment is rapidly gaining attention worldwide, although many developing countries have not accomplished much on the ground as many sustainability aspects still remain untreated. Despite their low greenhouse gas contributions to the globe, the high rate of construction activities that do not embrace sustainable practices in these countries pose challenges to the environment. Using the case of Tanzania, this study assesses the level of sustainability awareness among key stakeholders in the built environment.Design/methodology/approachThe study uses a mixed-method research approach where primary data was collected using a questionnaire and semi-structured interviews with key informants comprising engineers, architects, property managers, property owners, property users and academicians from institutions of higher learning.FindingsResults show that despite the potential for a sustainable built environment, there is a low level of awareness among key stakeholders. Whereas few architects, who were aware, admitted to have not incorporated sustainability aspects in their building design, other stakeholders did not have active roles in decision-making involving building construction projects. Compared to the rest, the awareness level of property users was the lowest. Lack of a specific policy or policy statement on sustainable building, high initial costs of sustainable building, few skilled professionals and lack of a broad choice of building materials are some of the factors accounting for the low level of sustainability adoption in the built environment.Originality/valueThe significance of this study lies within the objective of showing awareness levels of sustainability aspects among key built environment stakeholders and policymakers, which is important in devising strategies for promoting sustainable construction practices.