One of the dilemmas every school system in its developing process needs to face is the question what kind of school is just and fair - the one that provides the same opportunity for everyone, or the one which offers multiple roads to achieve similar results. Examining the fundamental principles of the nine-year primary school in Slovenia, it is clear that both approaches have been taken into consideration. Primary school in Slovenia (Year 1 to Year 9) should provide equal opportunity for everyone regardless of gender, social and cultural background, religion, ethnicity, physical and mental constitution, etc., while at the same time requires from teachers to take an individual and differentiating approach to pupils to ensure they can all achieve similar results. The question, therefore, is how teachers in practice accommodate the two principles, or, rather, which principle they favour. In our quest to answer this question, we will rely on a quantitative empirical research carried out on a representative sample of Slovenian primary school teachers. Using a semantic differential questionnaire, we asked teachers about personal traits of specific children. The semantic differential with 32 items was split up into four fields, such as efficacy, sociability, self-image and behaviour. Our aim was to find out how teachers defined just and fair school and what were their perceptions of children from diverse groups as encountered in school in Slovenia (e.g., girls and boys, children with special needs, poor and rich, children of ethnic background). Our analysis shows that in terms of personal traits the above mentioned groups are very different from the 'ordinary' children as well as one from another. It has also transpired that on the basis of the personal traits analysis some of the above mentioned groups fare considerably worse than others in terms of achieving good school results. The question then is what teachers are doing to accommodate these differences. The comparison between the teachers' definitions of fair and just school and the answers to a similar question within the diverse groups which were asked to describe the type of teaching they would require in respect to their specific difference brought some interesting results. The answers show that teachers in principle agree that teaching should be individual and differentiated; however, the answers from the diverse groups seem to indicate that teachers are failing to take responsibility for creating equal conditions and opportunity to learn for all. We would thus like to explore what opportunity is given to those groups which have come out of the personal trait analysis as 'less promising'. This question is even more important if we bear in mind that their school results are statistically significantly worse than those of 'ordinary' children.