Often uniforms are worn at private schools under the smocks. Secondary school Secondary school is for youths from 14 to 18. It takes 5 years. There are no uniforms at state schools. Private schools often do require uniforms.
Styles have varied iver time and from one school to another.
Most private schools required uniforms. Chronology Argentine school children commonly wear smocks. I'm not sure when that first begun, but continues into the 2000s. Other than the smock, state schools do not require uniforms. Primary children wear what ever they want under their smocks.