This study compared effective non-conventional and accredited private secondary schools in the city of Kisangani from 2012 to 2017, with the objective is identifying the characteristics of effective secondary schools and their determinants. To achieve this, we composed a survey questionnaire that was submitted to the head teachers of non-conventional and accredited public schools. The data collected from the latter were analysed and processed using a statistical software package (S.P.S.S). The overall results of the processing showed that the majority of teachers are hired either by test (most often in private schools) or by assignment (often in non-agreement schools); all the teachers working in these schools are qualified, as all of them are either graduates or licensees; while the head teachers of public schools believe that their teachers are satisfied with their salary, this is not the case for those of non-agreement schools who believe the opposite; All schools held pedagogical meetings with their teachers, but also with the parents’ committee; in most cases, the graduating students of the surveyed schools come from the same school, in the lower grades, are regular and disciplined; some schools operate in a conducive environment, while others operate in a non-conducive environment and within almost every school, there are pedagogical units, and the head teachers consider the efficiency of their schools to be satisfactory.