The present study aims to investigate effectiveness and equity in a private institution with a philanthropic nature and recognized academic prestige, located in the city of Juiz de Fora – MG. The theoretical framework was drawn up based on the concepts of equity by Rawls (2003) and Dubet (2004, 2008) and of school justice and positive discrimination proposed by Crahay (2000) and Dubet (2008), respectively. In a complementary manner, studies that approach the issues of effectiveness and school equity in the Brazilian context were also implemented. The research resorts to a longitudinal drawing and uses profile and results data from students in the three measures of development of Universidade Federal de Juiz de Fora - UFJF s Programa de Ingresso Seletivo Misto - PISM-UFJF, an exam that is applied at the end of each academic year of High School. The students results were organized in five comparison groups: the interest group, composed by students with a low socio-economic status that receive a scholarship to attend the philanthropic school, and other four comparison groups, one consisting of paying students of the philanthropic school and three consisting of students from public schools. In the data analysis, mixed methods were used: quantitative and qualitative. The first ones involved regression models to measure the effects of the socio-economic status on the students development on PISM and on career choices. Furthermore, qualitative analysis were developed from semi-structured interviews with scholarship-holding students and the philanthropic school s managers, the scripts of which were elaborated in relation with the characteristics of effective schools identified for Brazil by Alves and Franco (2008). The research findings confirm the significant correlation between socioeconomic status and the students proficiency identified in other research and points to the evidence of educational effectiveness and equity promoted by the philanthropic school. The quantitative analysis showed that scholarship-holding students achieved higher proficiency than students with similar characteristics from the comparison group enrolled in the other four schools. The results were also interpreted according to qualitative analysis and, in accordance with the Brazilian studies about school effectiveness, identified that internal school conditions such as infrastructure, academic environment, management, pedagogic emphasis and teacher performance are important effectiveness factors. The study also points to an issue that deserves a better investigation: the weight of the social origin on the scholarship-holding students choices of lower academic prestige careers, even if they attended an effective equity promoter and socially acknowledged excellence school during High School.