Education minister Prof Georgi Valchev has made Monday, 26 October, a day without lessons, but pupils can still go to school. The order covers all pupils in Bulgaria, the ministry's press office said.
Parents can leave their children at school, where staff will run activities. The ministry said parents will not have to change their work hours or find other childcare.
Bulgaria holds its presidential and vice-presidential election on Sunday, 25 October. Schools need time afterwards to get classrooms ready for normal lessons.
Teachers will move the material from the missed day to other lessons. The ministry says this will not harm the school year as a whole.
Parliament scheduled the election on 31 July. A total of 138 MPs from Progressive Bulgaria, the DPS and Vazrazhdane voted for it, and none voted against. Seven MPs from We Continue the Change abstained. GERB-SDS and Democratic Bulgaria did not vote.