International Mathematical Olympiad
Old IMO site
- excellent collection of links
International Tournament of Towns
- official page with problems from 1980. till now (in Russian)
The IMO Compendium
- thousands of olympiad problems, IMO shortlists and longlists, and other stuff.
Mathematical Competitions in Croatia
- elementary and high school
Competitions in Bulgardia
Competitions in Canada
- problems from Canadian and Asia-Pacific MO
- a variety of competitions and related resources
Competitions in Estonia
Competitions in Poland
- problems from Polish, Baltic, and Austrian-Polish mathematical competitions.
- (in Russian)
Competitions in United Kingdom
- R. Semizarov’s page with a lot of problems, some with solutions (in Russian)
- an active forum of Valentin Vornicu.
- a Canadian journal for high school - free access to older issues.
- Russian journal for high school, mathematics and physics - all volumes are available (in Russian)
- Hungarian Journal for high school math and physics (in English and Hungarian)
- Online jornal from Hong Kong (in English)
- online journal from Titu Andreescu (na engleskom)
Old page of Djordje Milicevic
- introduction to competitions for university students.
International Mathematics Competition for University Students
- also known as IMC, official page
Vojtĕch Jarník Annual International Mathematical Competition
- international student competition in Ostrava (in English)
William Lowell Putnam Competition
- American student competition.
Berkeley Math Circle
- weekly program for high school students in Bay Area.
Mathematical Problem Solving
Mathematical competitions in Slovenia
Mathematical Society of Serbia
Mathematical High School in Belgrade
Petnica Science Center
- a web site of Vojislav Andric with methodical approach to Diofantine equations.