This paper tests whether competition and collaboration as well as a broad range of other factors lead to improved efficiency in the UK independent school sector. These schools have always operated in a competitive environment, but collaborative groupings are also observed. To answer our main aim, a robust conditional efficiency estimation is employed. Greater efficiency is associated with higher market share, at least at the low levels of market share observed in the sector. There is also some evidence of a positive effect on efficiency of collaboration. Findings regarding the efficiency of schools in the independent sector will be of interest to both independent and state schools as Government policy in the UK has over time encouraged schools in the state sector to become more competitive as an initiative designed to enhance efficiency. The Government is also encouraging greater collaboration between state schools such that they gain benefits from collaboration and sharing of good practice.