The Olympiade Mathématique Belge (English: '''Belgian Mathematical Olympiad'''; OMB) is a mathematical competition for students in grades 7 to 12, organised each year since 1976. Only students from the French community participate, Dutch-speaking students can compete in the Vlaamse Wiskunde Olympiade.
The competition is split up in three age categories:
Among the participants, three are selected to represent Belgium in the International Mathematical Olympiad, together with three students selected through the Vlaamse Wiskunde Olympiade.
These three participants are chosen through a series of contests. The first round is the « éliminatoire » in which anyone who is eligible to participate in their own category can. Out of these students, about 10% of the highest scoring ones are selected to participate in the « demi-finale ». In this round, a similar multiple choice test (almost identical in layout to the first round) is given to the contestants. Out of the top-scorers from this round, participants are invited to take part in the « finale ». In this final test, 4 or 5 questions are given (instead of 30) and the answers and reasoning must be thoroughly explained. Finally, some promising students, from this final test, are then picked to attend a maths camp at which the 3 imo team members shall be selected.