While the sustainability concept has gained recognition in Indonesia, contractors have been slowly implementing the principles in construction projects. An assessment model was developed as a tool to identify the baseline conditions of contractors' readiness, i.e. awareness, willingness, and capacity towards sustainability practices. The model involves parameters and indicators derived from green building and green contractor concepts, and sustainable construction best practices. The scoring system for these parameters and indicators was set up through discussions with experts using the Delphi method facilitated by the Ministry of Public Works. Trial surveys were conducted to refine the model. A preliminary portrayal of existing conditions in Indonesia was assessed using the proposed readiness assessment model. This limited survey indicated that while large contractors are fully aware and willing, they have been only partly implementing sustainability practices. Because the process of developing the model had involved experts and champions of the industry/stakeholders, and was also led by the government/Ministry of Public Works, the proposed assessment model should be inherently acceptable for industry-wide application.