Secondary school during the existence of the USSR was transformed several times in accordance with the realities of changing life, all modifications were aimed at increasing the level of education of new generations. In the early years of Soviet power, general and vocational education were not separated: in the unified labor nine-year schools of the RSFSR, mastering the basics of theoretical knowledge and craft took place in parallel. The training was conducted in two stages: the first – five-year, the second – four-year. Additionally in 1919 at secondary specialized and higher educational institutions, labor departments were opened – working faculties that prepared illiterate proletarians and peasants to study at universities. They existed until the mid-1930s and were abolished as unnecessary. In 1932, secondary education in the USSR became ten–year and three–stage: primary - from 1st to 4th grade; incomplete secondary - from 5th to 7th; secondary – 10th grades.
During the Great Patriotic War, two types of specialized schools appeared in the education system of the USSR: Suvorov and Nakhimov schools, which were engaged in training applicants of higher military educational institutions; schools of working and rural youth, created so that workers in evening and correspondence form could receive secondary education.
In 1958, the structure of secondary education changed: the first three classes became primary, the fourth through eighth grades became secondary, and the ninth and tenth grades became senior. In the same year, the first technical schools were opened, and the schools of factory apprenticeship, which trained skilled workers on the basis of primary education, were replaced by vocational schools, where it was possible to enter after 8th grade to acquire a labor specialty. To support incomplete, large and low-income families, a system of boarding schools was developed in which children lived during the working week, studying as in a regular school, and went home on weekends. Extended day groups have been introduced in all secondary schools so that children who do not have grandparents can stay at school after the end of lessons until the evening, eating and doing homework under the supervision of teachers.
The secondary education system reformed in 1958 in the USSR remained unchanged until the collapse of the country and was recognized by many foreign authoritative figures of education as the best.