Recent socioeconomic changes have created and intensified paradoxical organizational tensions that companies in numerous industries, including the construction sector, need to address when organizing and managing their activities. The nature of these tensions has not been sufficiently explored in the existing construction management literature. Thus, this study analyzes tensions between control and flexibility at different organizational interfaces, as perceived by the managers of three large infrastructure projects that were parts of two different megaprojects in Sweden. The empirical findings highlight several tensions within three types of interfaces, that is, external, intraorganizational, and interorganizational tensions, that are important for both project managers and project owners to understand. This paper contributes to the project and construction management literature by illustrating the importance of a systemic paradox perspective, which is obtained by combining the paradox literature and principal-agent theory. A systemic paradox perspective is required to understand how tensions between control and flexibility are interpreted by different parties and how tensions in different organizational interfaces are interrelated and may be addressed to avoid suboptimization.