Closed since Monday, schools and universities reopened despite the alert still remaining at level 4, worrying many parents with two top suspects from the Paris attacks still at large.
"I had decided to not bring my kids in school this morning, but changed my mind late last night. Life must go on," said a 47-year-old father who drove his two daughters to school.
"Thank goodness we only have a half day today," said Marc, 14, as he boarded a school bus, adding that he fully enjoyed the two extra days off from school.
About 300 extra police from around Belgium were sent to Brussels to guard schools and 200 extra soldiers helped patrol the metro.
Museums and public concert halls were also to reopen, officials said.