The Kazakh government says it has reiterated a ban of the hijab, or head scarf, and any other clothing that "directly or indirectly propagates religion" in schools.
The Education Ministry said on October 19 that the decision was made following consultations between different ministries.
In January, Kazakhstan adopted a law banning the hijab in schools across the country.
However, a number of parents have complained that some children continue to attend class wearing a hijab.
Kazakh authorities have been increasingly concerned about religious extremism.
In June, a group of 25 alleged Islamic militants carried out a series of attacks in the northwestern city of Aqtobe.
Five civilians and three members of Kazakhstan's security forces were killed in the violence.
The country declared itself a secular state after it gained independence following the collapse of the Soviet Union in 1991.