In England, building regulations govern aspects of a building's environmental performance. The Building Control Surveyor reviews designs and on-site construction in order to evaluate, and ultimately certify, compliance with the regulations, but little research has been carried out to investigate the role of these professionals in promoting sustainable construction. A qualitative study was conducted, comprising semistructured interviews with 21 building control surveyors and four key informants from professional bodies in England. The building surveyors initially positioned their power as wholly derived from the regulations, thus constraining their contribution on sustainability to regulation enforcement. However, this stood in contradiction to their recognition of being valued and influential members of the project team. Descriptions of day-to-day activities included sharing common goals with the team, providing guidance based on their knowledge and experience, and developing collaborative relationships.Based on theories of power, these practices may be seen as processes of power. The primary conclusion is that building control surveyors are indeed powerful in the project team, and, with greater recognition of the varied forms of power available to them above and beyond regulatory certification, they could extend their influence in daily working interactions to promote more sustainable construction.