International competition is ruled by the FEI (Federalis Equestre Internationale).
Today, over 30 countries have national reining associations.

2014 World Equestrian Games, Normandy France - Team Canada

The first international competition was held in Gladstone, N.J., USA, in June 2000. Seven teams competed. They were the USA, Canada, Italy, Germany, Venezuela, Japan and Brazil. Every team except the USA and Canada rode borrowed horses. In 2001 NRHA and the AQHA announced that reining would be a medal event at the World Equestrian Games, being held in Spain, 2002.

In June 2002, the USET hosted another Nation’s Cup. Canadians rode borrowed horses. The top teams were: Team USA -Tim McQuay riding Okie Dun It, Craig Johnson riding Sailing Smart, Dell Hendricks riding Dunit In Hollywood, Shawn Flarida riding Freckles Top Prize; Team Canada - Francois Gauthier riding Don Quintana, Shawna Sapergia riding Jac Pic A Nic, Patrice St. Onge riding Start Me A Tab, and Team Brazil - Renata Mauri Ricca riding Scottin Little Lady, Franco Bertolani riding Peppy Sol Anson, Gilson Vieira Diniz Fihl riding Reys The Band, and Alexandre Lhanas Ramos riding Melon Kali Jac.
2002 Team medal results: Gold- USA, Silver- Canada, Bronze- Brazil   (right picture: Francois Gauthier, official coach of the 2014 Canadian Team)

Bob Thompson (Chef d’equipe), Patrice St. Onge, Jason Grimshaw, 
Francois Gauthier, Shawna Sapergia 
Photo: Mike Scott, Slidin’ 2002

In September 2002, the Canadian Team competed in the World Equestrian Games, Jerez, Spain. About 46 horse and riders would compete, representing countries from all over the world. The Canadian Team’s riders were: Francois Gauthier riding Ghost Buster Baby, Jason Grimshaw riding Listo Pollito Lena, Patrice St. Onge riding slip Me Another Kiss, and Shawna Sapergia riding Pretty Much Eagle. The Chef d’equipes were Bob Thompson and Molly Sapergia. 2002 Team medal results : Gold- USA, Silver- Canada, Bronze- Italy.

In 2004 the FEI started the World Reining Masters show, in which countries could compete for a yearly world championship. In 2004 sixteen countries competed in Oklahoma City, Oklahoma, USA. 

In 2006 was the next World Equestrian Games, in Aachen, Germany. It was the second time reining had been part of the event with a total purse of EUR 100,000. Teams from Austria, Belgium, Brazil, Canada, Czech Republic, Denmark, France, Great Britain, Germany, Israel, Italy, The Netherlands, Switzerland, Slovakia, Sweden and the USA competed along with individual riders from the Dominican Republic, Hungary, Mexico, Norway, Poland and South Africa. In order to be able to compete either as a member of a team or as an individual at the 2006 WEG, riders must have taken part in two FEI Reining competitions held in any country during the qualifying period, or competed at a National Federation CRIO with a team during the same period.

Members of the Canadian Team were: Duane Latimer riding Hang Ten Surprize, Luke Gagnon riding Lil Santana, Lance Griffin riding Whiz N Tag Chex, and Francois Gauthier riding Snow Gun.

http://www.reiningcanada.com/international/international_news.htm