American Regions Math League (ARML)
Results and past problems for the ARML, an annual national competition.
British Mathematical Olympiad
The Subtrust (BMOS) and Committee (BMOC) pages with past problems.
Bulgarian Competitions in Mathematics and Informatics
Introduction to the major national competitions in Bulgaria. Features comprehensive sets of past contest problems.
Canadian Mathematics Competition
Organization that sponsors the Canadian Open Mathematics Challenge, the Euclid Contest, the Gauss Contest, with online workshop, problem archives, and other resources for students.
Dutch Mathematics Olympiad
Annual mathematics competition for high school students since 1962.
Harvard-MIT Mathematics Tournament
Annual math tournament for high school students, held at MIT and at Harvard in alternating years.
Math League
Specializes in math contests, books, and computer software designed for students from the 4th grade through high school.
MathCounts
United States national math coaching and competition program for middle school students.
Polish Mathematical Olympiad
Math olympiads for Polish high school students. Features problem archives from the Austrian-Polish Mathematics Competition, Baltic Team Contest, Poland Mathematical Olympiad.
The Canadian Open Mathematics Challenge
Qualifying round for the Canadian Mathematical Olympiad. Site includes registration and past problems.
The Mandelbrot Competition
Includes introduction to contest, news, memos, resources and on-line registration.
UIUC Math Contests Webpage
Information and resources for the Putnam and the UIUC Undergraduate Math Contest. Includes practice problems and solutions. Maintained by Professor A.J. Hildebrand.