
American Samoa entered only one athlete to compete at the 2007 World Championships in Athletics: 100 metres runner Mathew Lagafuina.

Anguilla competed at the 2007 World Championships in Athletics with 2 athletes.

Belgium competed at the 2007 World Championships in Athletics with 18 athletes.

Bosnia and Herzegovina competed at the 2007 World Championships in Athletics from 24 August – 2 September 2007.

Canada competed at the 2007 World Championships in Athletics with 30 athletes. In order to qualify the athletes had met the world championship qualification standards. The qualification for the world Championship took place in early July at the Windsor Stadium in Windsor, Ontario. The highlighted event at the trials was the Woman's 100m Hurdles featuring "2003 World outdoor and indoor champion Perdita Felicien, Angela Whyte, and Priscilla Lopes who finished 1-3 respectively during the 2006 national championships". The Championships took place in Osaka, Japan in the Nagai Stadium and were the 11th World Championships held under the IAAF sanctions. The event lasted nine days spanning from August 25 to September 2.

China competed at the 2007 World Championships in Athletics.

Croatia competed at the 2007 World Championships in Athletics with 4 athletes.

Estonia competed at the 2007 World Championships in Athletics.

France has been represented by 54 athletes at the 2007 World Championships in Athletics. Romain Mesnil and Yohann Diniz won France's two silver medals. France sent a young squad, with 29 of the 54 total athletes under 25 years old (53%).

The United Kingdom of Great Britain and Northern Ireland competed under the shortened name of Great Britain and Northern Ireland at the 2007 World Championships in Athletics.

Greece participated with a team of 27 athletes at the 2007 World Championships in Athletics in Osaka, Japan.

Hungary will competes at the 2007 World Championships in Athletics with 11 athletes.

Ireland competed at the 2007 World Championships in Athletics in Osaka, Japan. The Irish team was made up of 15 athletes competing in 13 events. Despite not winning any medals, the team was thought to have performed excellently by Irish commentators. Ireland's highest placed finishers were Eileen O'Keefe in the women's hammer throw and Robert Heffernan in the men's 20K walk, both of whom finished in 6th place. Only one national record was set, by Joanne Cuddihy in the women's 400m semi-final. Despite none of them making the final, Ireland's sprinters were perhaps the most impressive performers with David Gillick, Paul Hession, Derval O'Rourke and Cuddihy all reaching the semi-finals and being ranked inside the top 16.

Israel sent 7 competitors to the 2007 World Championships in Athletics.

Italy was represented by 36 athletes at the 2007 World Championships in Athletics.

Kenya competed at the 2007 World Championships in Athletics held at Nagai Stadium in Osaka, Japan from 24 August to 2 September 2007. Kenya won five gold, three silver and five bronze medals, finishing second in the medal table, after the United States.

Latvia competed at the 2007 World Championships in Athletics with a squad of 11 athletes.

New Zealand competed at the 2007 World Championships in Athletics with a team of ten athletes. Valerie Vili won New Zealand's only medal with a gold medal in the women's shot put.

Poland competed at the 2007 World Championships in Athletics in Osaka, Japan, from 25 August – 2 September 2007.

Slovenia was represented at the 2007 World Championships in Athletics by 12 athletes.

South Africa competed at the 2007 World Championships in Athletics, but did not win any medals.

South Korea competed at the 2007 World Championships in Athletics from August 25 to September 2. A team of 11 athletes was announced in preparation for the competition.

The United States competed at the 2007 World Championships in Athletics.