This paper examines the role of school climate and socio-demographic characteristics in explaining student achievement in the Ilača-Banovci Elementary School. Due to the heterogeneity of students with respect to various factors, this study focused on the sociodemographic characteristics of students and their families, namely students age and gender, parents’ employment, parents’ education, income and family structure. This paper presents specific research problems: to examine the differences in school achievement and perception of school climate in students' of different socio-demographic characteristics, as well as the relationship between students' perception of school climate and students' school achievement. To measure the school climate the Croatian School Climate Questionnaire for Students (HUŠKU, Velki and Antunović, 2014) was used. In accordance with the set goals, the differences in school achievement of students of different socio-demographic characteristics (age and gender of students and employment of parents, education and employment of parents, income and family structure) were analyzed first and then the differences in perception of school climate with regard to the same socio-demographic features. After that, the correlation between school achievement and perception of school climate was calculated. A statistically significant difference in overall school achievement was obtained with respect to the grade that students attend. At the same time, 5th and 6th grade students achieve slightly better school successes at the end of the 2019/20 school year in comparison to the 7th and 8th grade students. Students' school success did not statistically significantly differ with respect to the other socio-demographic characteristics. The overall result in the questionnaire was formed and it can be concluded that students perceive the school climate very positively and that students' perception of the climate is not related to school achievement.