The prolonged pandemic situation that left its damaging footprints not only in global economy but in many families, struggling with options to maintain their pre-pandemic income levels and social status, has raised the issue about the impact of family socioeconomic status (SES) on child’s personality, especially self-beliefs. It has been previously studied that SES has a significant impact on child’s academic achievement. Inherited social status has been the subject of studies for many years, and some researchers argue that it is rooted in the child’s self-beliefs. The aim of this article is to examine the impact of family SES factors. The research question for this study is as follows: does family SES impact significantly primary school students’ academic self-beliefs? To evaluate the significance of factor impact, the authors used linear regression models where the dependent variable was students’ self-beliefs, but family SES and students’ achievement were the independent variables. The authors analysed the students’ questionnaire data collected from such studies as the International Association’s for the Evaluation of Educational Achievement (IEA) Progress in International Reading Literacy Study (PIRLS) 2016, Trends in International Mathematics and Science Study (TIMSS) 2019, International Civic and Citizenship Education Study (ICCS) 2016 and OECD Programme for International Student Assessment (PISA) 2018. In particular, the students’ questionnaire data from countries around the Baltic Sea were explored. The results of this study demonstrated a small but significant impact of family SES on the child’s self-perception. If SES was analysed in linear regression models together with achievement, the models explained variations from 16–25% for academic self-concept in reading, 14–27% for academic self-concept in Mathematics, 3–13% for academic self-concept in Science of Grade 4 students, and 1–7% of variation for Grade 8 students’ self-efficacy in citizenship, 10–18% of variation for 15 year old students’ academic self-concept in reading, 2–7% for academic self-concept in finance, and 6–12% of 15 year old students’ global self-efficacy.