The English education sector is undergoing major restructuring with the coalition government placing great emphasis on two key principles of policy: deregulation and marketisation. This development follows on two decades in which the British state has sought to raise performance levels and reduce costs through a variety of policies that are drawn broadly from the New Right. Sixth form colleges are a small sector of the post-16 education system, numbering 94 in total and largely concerned with university entrance. As a result of the "opening-up" of the education market post-2010, they are confronted not only by the much larger general further education colleges and the better-funded school sector, but also by the likelihood of new forms of competition and predatory threats from competitors. Organisational theory offers two competing visions of how institutions may respond to environmental change: isomorphism and adaptation. This paper will explore the validity of these two theoretical positions and consider how sixth form colleges may respond to the changes taking place.