This paper employs a stochastic production frontier model to assess the efficiency of the senior secondary schools in the Gambia. It examines their efficiency in using and mixing the educational inputs of average teacher salary, average teacher education, average teacher experience and students-to-teacher ratio in producing the number of students scoring credit and above in English and Mathematics. The schools are categorized into three types: the Government schools, the subsidized schools, and the private schools. The paper finds no evidence that the private schools are different from the subsidized schools, but there is robust evidence that the private schools are significantly different from the Government schools. The average teacher salary is found to be irrelevant to the student performance, whereas high average teacher experience significantly improves student performance, and high student-to-teacher ratio significantly negates the student performance. Private schools appear to be the most efficient in 2006, but from 2007 to 2008, the performance of the schools in general is found to be highly volatile and unpredictable. Only one school emerges to consistently maintain a superior efficient performance throughout the three years studied.