Abstract The aim of this article is to evaluate the efficiency of cities of the State of Rio de Janeiro in relation to municipal expenditures on education, as well as to identify the reasons that lead to inefficiency. In order to achieve the initial goal, this study uses DEA technique. The DMUs are 69 cities of the State of Rio de Janeiro. This paper uses following variables as inputs: municipal expenditure on elementary school, number of teachers of 9th grade of elementary school and number of students enrolled in 9th grade of elementary school. The following variables are used to compose output information: number of students who achieved advanced or proficient level in Portuguese and number of students who achieved advanced or proficient level in Mathematics. All data refer to the year 2013. In this study, output-oriented BCC model is used and, for its application, SIAD V3.0 software was used. GIS-DEA integration and some variables external to modelling were used to identify aspects that led to the inefficiency of some DMUs. This study concludes that cities that displayed a good performance are located in the least economically developed regions and that teachers’ average salary is an important motivational factor.