This work presents the results from measurements of radon concentrations in primary and high school education institutions—including their gymnasiums—from the Chisinau municipality and various rayons from the central and southern part of the Republic of Moldova. In the research carried out during the years of 2013–2014 and 2021, there were 78 (29 + 49) premises included, respectively, and 149 and 23,805 investigations were performed using RTM-1642 (active measurements) and RadonEye⁺² devices (passive measurements). The results show an essential variability for the studied radio-stressogenic factor, depending on the geological conditions of the location of the premises and the age of the building. Thus, during 2013–2014, the minimum concentration of radon detected was 26 Bq m⁻³, and the maximum detected was 607 Bq m⁻³. In 2021, the results denote an indicator variability in the range of 17.4–657.9 Bq m⁻³ for early education institutions, with an average value of 127.6 Bq m⁻³, and denote a range of 231.8–1129.3 Bq m⁻³, with an average value of 665.4 Bq m⁻³), for high school education institutions and their gymnasiums. The effective annual dose for the children in a classroom varies between an interval of 0.21–4.88 mSv y⁻¹ (average 1.19 mSv y⁻¹) and 0.14–9.08 mSv y⁻¹ (average 1.29 mSv y⁻¹) for the 2013–2014 and 2021 surveys, respectively.