- Isto Aho, Finland (2000 - 2001, IOI'01 HSC) tyisah_at_cs.uta.fi
- Bojan Antolović, Croatia (2006 - 2007, Chair IOI'07 HSC), bojan.antolovic_at_omega-software.hr
- Zvonimir Bujanović, Croatia (2007 - 2007, Vice Chair IOI'07 HSC, ISC member), zbujanov_at_math.hr
- Hal Burch, United States of America (2002 - 2003, IOI'03 HSC), hburch_at_lumeta.com
- Benjamin Burton, Australia, (2008 - 2014, elected, host IOI'13), bab_at_debian.org
- Cesar Cepeda, Mexico (2004 - 2008, elected Chair IOI'06 HSC, ISC Chair March 2007-?), cesarSC_at_auronix.com
- Kyung-Yong Chwa, Korea (2000 - 2003, Chair IOI'02 HSC), kychwa_at_jupiter.kaist.ac.kr
- Krzysztof Ciebiera, Poland (2004 - 2005, IOI'05 HSC),ciebiera_at_mimuw.edu.pl
- Gordon Cormack, Canada (2004 - 2011, Chair, IOI'2010 HSC), gvcormack_at_uwaterloo.ca
- Jittat Fakcharoenphol, Thailand (2009 - 2012, Chair, IOI 2011 HSC), jittat_at_gmail.com
- Michal Forišek, Slovakia (2006 - 2013, elected, reelected 2009 , 2012 for 1 year to replace the late Mihai Pătraşcu), misof_at_ksp.sk
- Iphigenia Founta, Greece (2002 - 2003, IOI'04 HSC), ifounta_at_teiath.gr
- Greg Galperin, United States of America (2001 - 2004, Chair IOI'03 HSC), grg-webvisible_at_ai.mit.edu
- Mohammad Ghodsi, Iran (1999 - 2000, GA-elected), ghodsi_at_sina.sharif.ac.ir
- Roberto Grossi, Italy (2009 - 2013, host IOI'12), grossi_at_di.unipi.it
- Michalis Hatzopoulos, Greece (2002 - 2005, Chair IOI'04 HSC), mike_at_di.uoa.gr
- Gyula Horváth, Hungary (1999 - 2001, GA-elected, Chair IOI'96 HSC), horvath_at_inf.u-szeged.hu
- Artem Iglikov, Kazakhstan (2012 - 2016, host IOI'15) artem.iglikov_at_gmail.com
- Ossama Ismail, Egypt (2006 - 2009, Chair IOI'08 HSC), ossama_at_aast.edu
- Marcin Kubica, Poland (2003 - 2010, elected, Chair IOI'05 HSC), kubica_at_mimuw.edu.pl
- Mansur Kutybaev, Kazakhstan (2012 - 2016, host IOI'15) mansur165_at_gmail.com
- Pangfeng Liu, Taiwan (2011 - 2015, host IOI'14), pangfeng_at_csie.ntu.edu.tw
- Mohhammad Mahdian, Iran (2015 - 2016, host IOI'17) mahdian_at_gmail.com
- Martin Mareš, Czech Republic (2006 - 2015, ITWG chair, elected, reelected 2009 and 2012) mj_at_ucw.cz
- Ian Munro, Canada (2000 - 2003, elected), imunro_at_uwaterloo.ca
- Fredrik Niemelä, Sweden (2011 - 2014, elected) fredrik_at_niemela.se
- Jyrki Nummenmaa, Finland (1999 - 2002, 2003 - 2006, Chair ITWG; Chair IOI'01 HSC), jyrki_at_cs.uta.fi
- Xenofon Papadopoulos, Greece (2002 - 2003, IOI'04 HSC), xenofon_at_edu.teiath.gr
- Kunsoo Park, Korea (2001 - 2002, IOI'02 HSC) kpark_at_theory.snu.ac.kr
- Mihai Pătraşcu, Romania (2010 - 2012, elected)
- Djura Paunic, Yugoslavia (2001 - 2004, elected), djura_at_unsim.im.ns.ac.yu
- Richard Peng, USA, rpeng_at_cc.gatech.edu (2014 - 2018, elected, reelected 2015)
- Lovro Pužar, Croatia (2006 - 2008, IOI'07 HSC), lovro_at_mail.inet.hr
- Luis Cruz Romo, Mexico (2005 - 2006, IOI'06 HSC), lucruz_at_ipn.mx
- Alen Spiegl, Croatia (2006 - 2006, Temporary Chair IOI'07 HSC), alen.spiegl_at_vip.hr
- Krzysztof Stencel, Poland (2004 - 2005, IOI'05 HSC), stencel_at_mimuw.edu.pl
- Ismail Hakki Toroslu, Turkey (2003 - 2006, elected, Chair IOI'99 HSC, (ISC member 1999-2000, re-elected 2003), toroslu_at_ceng.metu.edu.tr
- Velin Tzanov, Bulgaria (2007 - 2010, Chair IOI'09 HSC), ioi_at_tzanov.com
- Tom Verhoeff, Netherlands (2005 - 2007, elected, Chair IOI'95 HSC, ISC member 1999-2005, re-elected 2005, ISC Chair 1999-March 2007), T.Verhoeff_at_tue.nl
- Wenhu Wu, China (1999 - 2000, Chair IOI2000 HSC), wuwh_at_mail.tsinghua.edu.cn
- Baolin Yin, China (1999 - 2001, Vice-Chair IOI2000 HSC), yin_at_cs.sebuaa.ac.cn and yin_at_nlsde.sebuaa.edu.cn
- Francisco Zaragoza Martínez, Mexico (2005 - 2006, IOI'06 HSC), franz_at_correo.azc.uam.mx
- Ali Sharifi Zarchi, Iran (2012 - 2014, elected), asharifi_at_sharif.ir
- Hamid Zarrabi-Zadeh, Iran (2014 - 2015, host'17), zarrabi_at_sharif.edu
