| ZWE | Zimbabwe | A Stewart <stewarta@maths.uz.ac.zw> | | |
| YUG | Yugoslavia | | | 1967, 1977 |
| VNM | Vietnam | Nguyễn Khắc Minh <nkminh@moet.edu.vn> | | 2007 |
| VEN | Venezuela | Rafael Sánchez <lamonedar@gmail.com> | http://www.acm.ciens.ucv.ve/ | |
| UZB | Uzbekistan | Shuhrat Ismailov <shuhrat.n.ismailov@gmail.com> | http://matholymp.zy.uz | |
| USS | Union of Soviet Socialist Republics | | | 1964, 1968, 1973 |
| URY | Uruguay | Nelson Chocca <nchoccasou@hotmail.com> | http://www.reu.edu.uy/jpv/proyectos/cpm/ | |
| USA | United States of America | Steven Dunbar <sdunbar@maa.org> | http://amc.maa.org | 1981, 2001 |
| UNK | United Kingdom | Geoff Smith <G.C.Smith@bath.ac.uk> | http://www.bmoc.maths.org/ | 1979, 2002 |
| UAE | United Arab Emirates | Aaesha Jassem Alshamsi <ammk66@hotmail.com> | | |
| UKR | Ukraine | Bogdan Rublov <rublyovbv@gmail.com> | http://matholymp.org.ua/ | |
| UGA | Uganda | Okello Jasper <jokello@isae.mak.ac.ug> | | |
| TKM | Turkmenistan | Erol Aslan <erolmat@yahoo.com> | | |
| NCY | Turkish Republic of Northern Cyprus | | | |
| TUR | Turkey | Azer Kerimov <kerimov@fen.bilkent.edu.tr> | http://www.matematikolimpiyati.org/ | 1993 |
| TUN | Tunisia | Taoufik Charrada <tawfik.charrada@gmail.com> | | |
| TTO | Trinidad and Tobago | Indra Haraksingh <iharaksingh@yahoo.com> | | |
| THA | Thailand | Yotsanan Meemark <Yotsanan.m@chula.ac.th> | | 2015 |
| TZA | Tanzania | | | |
| TJK | Tajikistan | Umed Karimov <umedkarimov@gmail.com> | | |
| TWN | Taiwan | Cheng-Der Fuh <stcheng@stat.sinica.edu.tw> | | 1998 |
| SYR | Syria | Emad Al-Azab <emadalazab@gmail.com> | http://www.syrolympsc.org | |
| SUI | Switzerland | Raphael Steiner <raphaelsteiner@gmail.com> | http://www.imosuisse.ch/ | |
| SWE | Sweden | Paul Vaderlind <paul@math.su.se> | http://www.mattetavling.se | 1991 |
| LKA | Sri Lanka | C. J. Wijeratne <chanakya_wijeratne@yahoo.com> | http://www.slmathsolympiad.org/ | |
| ESP | Spain | María Gaspar <mgaspar@mat.ucm.es> | http://platea.pntic.mec.es/~csanchez/olimmain.htm | 2008 |
| SAF | South Africa | Johan Meyer <meyerjh@ufs.ac.za> | http://www.samf.ac.za | 2014 |
| SVN | Slovenia | Gregor Dolinar <gregor.dolinar@fe.uni-lj.si> | http://www.dmfa.si/ | 2006 |
| SVK | Slovakia | Peter Novotný <pnovotny@fmph.uniba.sk> | http://skmo.sk | |
| SGP | Singapore | June Tan <tan_hwee_chiat@moe.gov.sg> | http://sms.math.nus.edu.sg/ | |
| SCG | Serbia and Montenegro | | | |
| SRB | Serbia | Đorđe Krtinić <georg@matf.bg.ac.rs> | http://srb.imomath.com/ | |
| SEN | Senegal | Samba Dabo <sdabo345@gmail.com> | | |
| SAU | Saudi Arabia | Fawzi A. Al-Thukair <thukair@ksu.edu.sa> | http://www.smo.org.sa | |
| SLV | El Salvador | Carlos Mauricio Canjura Linares <carlos_canjura@yahoo.com> | | |
| RUS | Russian Federation | Nazar Agakhanov <nazar_ag@mail.ru> | http://math.rosolymp.ru/ | 1992 |
| ROU | Romania | Radu Gologan <radu.gologan@imar.ro> | http://rms.unibuc.ro | 1959, 1960, 1969, 1978, 1999 |
| PRI | Puerto Rico | Luis F. Cáceres <luis.caceres1@upr.edu> | http://ompr.pr/ | |
| POR | Portugal | Joana Teles <jteles@mat.uc.pt> | http://www.spm.pt/olimpiadas | |
| POL | Poland | Michał Pilipczuk <michal.pilipczuk@ii.uib.no> | http://www.om.edu.pl/ | 1963, 1972, 1986 |
| PHI | Philippines | Jose Ernie C. Lope <ernie@math.upd.edu.ph> | http://mathsci.math.admu.edu.ph/pmo | |
| PER | Peru | Mariano González Ulloa <mgonzal@pucp.edu.pe> | http://www.somape.org.pe | |
| PAR | Paraguay | Gabriela Gómez Pasquali <gabriela@omapa.org.py> | http://www.omapa.org.py | |
| PAN | Panama | Pedro A. Marrone G. <pmarrone@opm.org.pa> | http://www.opm.org.pa/ | |
| PAK | Pakistan | Alla Ditta Choudary <choudary@cwu.edu> | | |
| NOR | Norway | Harald Hanche-Olsen <hanche@math.ntnu.no> | http://abelkonkurransen.no/ | |
| NGA | Nigeria | Adewale Solarin <asolarin2002@yahoo.com> | http://www.nmcabuja.org | |
| NIC | Nicaragua | Carlos Walsh <carjowalmen@yahoo.com.mx> | | |
| NZL | New Zealand | Christopher Tuffley <C.Tuffley@massey.ac.nz> | http://www.mathsolympiad.org.nz | |
| NLD | Netherlands | Quintijn Puite <g.w.q.puite@tue.nl> | http://wiskundeolympiade.nl/ | 2011 |
| MOZ | Mozambique | Luis de Nascimento Paulo <nascimento@mined.gov.mz> | | |
| MAR | Morocco | BERRAHO Mohamed <med.berraho@gmail.com> | | |
| MNE | Montenegro | Tatjana Vujosevic <tatjana.vujosevic@iccg.edu.me> | | |
| MNG | Mongolia | Dashdorj Ts <dashdorj_ts@yahoo.com> | | |
| MDA | Republic of Moldova | Ceapa Valentina <ceapa_valentina@yahoo.com> | | |
| MEX | Mexico | José Antonio Gómez Ortega <jago@ciencias.unam.mx> | http://www.omm.unam.mx | 2005 |
| MRT | Mauritania | Ould Farajou Isselmou <farajou@yahoo.fr> | http://www.resafad.mr/OlympiadesRIM.html | |
| MAS | Malaysia | M. Suhaimi Ramly <msuhaimi@gmail.com> | http://www.persama.org.my/ | |
| MKD | The former Yugoslav Republic of Macedonia | Vesna Manova - Erakovik <vesname@iunona.pmf.ukim.edu.mk> | | |
| MAC | Macau | Ieng Tak Long <itleong@umac.mo> | | |
| LUX | Luxembourg | Charles Leytem <charles.leytem@education.lu> | http://math.uni.lu/matholymp | |
| LTU | Lithuania | Romualdas Kasuba <romualdas.kasuba@mif.vu.lt> | http://www.olimpiados.lt/ | |
| LIE | Liechtenstein | Philipp Wirth <philippwirth@bluewin.ch> | | |
| LVA | Latvia | Dace Bonka <nms@lu.lv> | http://nms.lu.lv | |
| KGZ | Kyrgyzstan | Boljiev Buras Asanbekovich <boljiev_b@mail.auca.kg> | | |
| KWT | Kuwait | Adnan Abdulmuhsen <Cjakmian@kfas.org.kw> | | |
| KSV | Kosovo | Ramadan Limani <r_limani@yahoo.com> | | |
| KOR | Republic of Korea | Yongjin Song <yjsong@inha.ac.kr> | http://www.kms.or.kr | 2000 |
| PRK | Democratic People's Republic of Korea | Ham YongChol <arirang.pust@gmail.com> | | |
| KAZ | Kazakhstan | Sholpan Kirabayeva <daryn.intel@gmail.com> | | 2010 |
| JPN | Japan | Kazuaki Kobayashi <kazuaki@lab.twcu.ac.jp> | http://www.imojp.org | 2003 |
| CIV | Ivory Coast | Adama Coulibaly <couliba@yahoo.fr> | | |
| ITA | Italy | Roberto Dvornicich <dvornic@dm.unipi.it> | http://olimpiadi.dm.unibo.it/ | |
| ISR | Israel | Lev Radzivilovsky <levr78@hotmail.com> | http://www.weizmann.ac.il/zemed/gillis | |
| IRL | Ireland | Tom Laffey <thomas.laffey@ucd.ie> | http://www.irmo.ie | |
| IRN | Islamic Republic of Iran | Arash Rastegar <rastegar@sharif.edu> | http://www.ysc.ac.ir | |
| IDN | Indonesia | Al Haji Akbar Bachtiar <alhaji1104@yahoo.com> | | |
| IND | India | Jayashree Ramadas <director@hbcse.tifr.res.in> | http://cce.iisc.ernet.in/math.html | 1996 |
| ISL | Iceland | Friđrik Diego <fd@hi.is> | http://staefelag.raunvis.hi.is/node/2 | |
| HUN | Hungary | József Pelikán <pelikan@cs.elte.hu> | | 1961, 1970, 1982 |
| HKG | Hong Kong | Pui-Tin Chan <ptchan@edb.gov.hk> | | 1994, 2016 |
| HND | Honduras | Comité Hondureño de Olimpiadas Matemáticas <larmandoramos@gmail.com> | | |
| GTM | Guatemala | Dorval Carías <dorvalcs@gmail.com> | | |
| HEL | Greece | Anargyros Fellouris <info@hms.gr> | http://www.hms.gr | 2004 |
| GER | Germany | Hans-Dietrich Gronau <gronau@uni-rostock.de> | http://www.mathematik-olympiaden.de/ | 1989, 2009 |
| GDR | German Democratic Republic | Hans-Dietrich Gronau <gronau@uni-rostock.de> | | 1965, 1974 |
| GEO | Georgia | George Chelidze <g_chelidze@hotmail.com> | | |
| FRA | France | Claude Deschamps <cl.deschamps@free.fr> | http://www.animath.fr/ | 1983 |
| FIN | Finland | Matti Lehtinen <matti.lehtinen@helsinki.fi> | http://solmu.math.helsinki.fi/olympia/ | 1985 |
| EST | Estonia | Härmel Nestra <harmel.nestra@ut.ee> | http://www.math.olympiaadid.ut.ee/ | |
| ECU | Ecuador | Vicente Torres Álvarez <vitorres906@gmail.com> | | |
| DEN | Denmark | Kirsten Rosenkilde <kirstenrosenkilde@gmail.com> | http://www.georgmohr.dk/ | |
| CZS | Czechoslovakia | | | 1962, 1971, 1984 |
| CZE | Czech Republic | Martin Panák <naca@math.muni.cz> | http://www.math.muni.cz/mo | |
| CYP | Cyprus | Gregory Makrides <makrides.greg@usa.net> | http://www.cms.org.cy | |
| CUB | Cuba | Iliana Linares <linares@mined.rimed.cu> | | 1987 |
| HRV | Croatia | Željko Hanjš <hanjs@math.hr> | http://www.matematika.hr/domaca | |
| CRI | Costa Rica | Luis Gómez Rodríguez <olcomacr@gmail.com> | http://www.cidse.itcr.ac.cr/olimpiadas | |
| CIS | Commonwealth of Independent States | | | |
| COL | Colombia | María Falk de Losada <mariadelosada@gmail.com> | http://olimpia.uan.edu.co | 2013 |
| CHN | People's Republic of China | Qian Cheng <chinascienceolympiad@yahoo.com.cn> | | 1990 |
| CHI | Chile | Hernan Burgos <hburgos@ufro.cl> | http://www.olimpiadadematematica.cl/ | |
| CAN | Canada | Johan Rudnick <director@cms.math.ca> | http://www.cms.math.ca/Olympiads/ | 1995 |
| KHM | Cambodia | Sokly Lim <soklylim2003@yahoo.com> | | |
| BGR | Bulgaria | Nikolai Nikolov <nik@moi.math.bas.bg> | http://www.math.bas.bg | 1966, 1975 |
| BRU | Brunei | Syed Rozman bin Haji Syed Abd Rahim <rozmansr@hotmail.com> | | |
| BRA | Brazil | Nelly Carvajal <obm@impa.br> | http://www.obm.org.br/ | 2017 |
| BIH | Bosnia and Herzegovina | Muharem Avdispahić <mavdispa@pmf.unsa.ba> | | |
| BOL | Bolivia | Sonia Cordero Cárdenas <sonia_cordero_de_r@yahoo.com> | | |
| BEN | Benin | Kpamegan Bernardin <kpamegan_bernadin@yahoo.fr> | | |
| BEL | Belgium | Bart Windels <bart.windels@telenet.be> | https://www.vwo.be/vwo/belgianmatholympiads | |
| BLR | Belarus | Alena Senchanka <senchenko@minedu.unibel.by> | | |
| BGD | Bangladesh | A A Munir Hasan <munir.hasan@matholympiad.org.bd> | http://www.matholympiad.org.bd/ | |
| BAH | Bahrain | | | |
| AZE | Azerbaijan | Fuad Garayev <karayev62@yahoo.com> | | |
| AUT | Austria | Robert Geretschläger <robert.geretschlaeger@brgkepler.at> | http://www.oemo.at/ | 1976 |
| AUS | Australia | Mike Clapper <mike.clapper@amt.edu.au> | http://www.amt.edu.au/ | 1988 |
| ARM | Armenia | Artur Hovhannisyan <hovhan_artur@yahoo.com> | http://www.olymp.am | |
| ARG | Argentina | Patricia Fauring <patri@cbc.uba.ar> | http://www.oma.org.ar/ | 1997, 2012 |
| ALG | Algeria | Ali Atia <mengolfdz@yahoo.fr> | | |
| ALB | Albania | Fatmir Hoxha <fat.hoxha51@gmail.com> | | |
