The measures were taken after two staff members at the department's headquarters contracted the virus.
The department said the affected employees and their families are receiving support.
In accordance with the World Health Organisation (WHO) protocols, all other staff members who were in contact with them had gone for testing and would follow all protocols to prevent the spread of the virus.
The Gauteng department of education's two buildings in Simmonds and Loveday streets in Johannesburg were closed for disinfection. They are due to reopen on Monday.
“We wish all our staff members who tested positive a speedy recovery. You enjoy our support at all times,” said Lesufi.