The links between the theoretical issues influencing the structure of construction project organizations are discussed. The impact of the environment of a construction project and the technological sophistication of the project are considered in terms of how these factors shape project organizations. The environment is variously assayed for its complexity, its dynamism and its hostility. The technology used in projects is assessed by its level of certainty (whether it is well understood), its complexity and the level of interdependence between subactivities in the project. The variables are used to formulate hypotheses concerning their impact upon the structuring of construction projects and these are studied in 18 case studies. The research has been developed within an interpretive (phenomenological) paradigm. The findings suggest that complex environments lead to greater decentralization of authority, mainly by delegation. In the dimension of technology, complexity led to a wider use of liaison devices on projects with a greater number of technical functional specialists being used by projects. As projects become more technically interdependent then informality and flexibility are the principal mechanisms of project control.