The Association of Tennis Professionals (ATP) is the governing body of the men's professional tennis circuits – the ATP Tour, the ATP Challenger Tour and the ATP Champions Tour. It was formed in September 1972 by Donald Dell, Jack Kramer, and Cliff Drysdale to protect the interests of professional tennis players, and Drysdale became the first president. Since 1990 the association has organized the ATP Tour, the worldwide tennis tour for men and linked the title of the tour with the organization's name. It is the governing body of men's professional tennis. In 1990 the organization was called the ATP Tour, which was renamed in 2001 as just ATP and the tour being called ATP Tour. In 2009 the name of the tour was changed again and was known as the ATP World Tour, but changed again to the ATP Tour by 2019. It is an evolution of the tour competitions previously known as Grand Prix tennis tournaments and World Championship Tennis (WCT). The ATP's global headquarters are in London. ATP Americas is based in Ponte Vedra Beach, Florida; ATP Europe is headquartered in Monaco; and ATP International, which covers Africa, Asia and Australasia, is based in Sydney, Australia.
The ATP Tour is the sole worldwide top-tier tennis tour for men organized by the Association of Tennis Professionals founded in 1990 that replaced the earlier dual Grand Prix Circuit and WCT Circuit. The second-tier tour is the ATP Challenger Tour and the third-tier is the ITF Men's World Tennis Tour. The equivalent women's organisation is the WTA Tour.
The ATP International Series was a series of professional tennis tournaments held internationally as part of the ATP Tour from 2000 to 2008.
The ATP Challenger Tour is the secondary professional tennis circuit organized by the ATP. The 2009 ATP Challenger Tour calendar comprised 20 top tier Tretorn SERIE+ tournaments, and 142 regular series tournaments, with prize money ranging from $25,000 up to $150,000.
The ATP Challenger Tour is the secondary professional tennis circuit organized by the ATP. The 2010 ATP Challenger Tour calendar comprises 13 top tier Tretorn SERIE+ tournaments, and approximately 150 regular series tournaments, with prize money ranging from $35,000 up to $150,000.
The ATP Challenger Tour was the secondary professional tennis circuit organized by the Association of Tennis Professionals (ATP). The 2011 ATP Challenger Tour calendar comprised 15 top tier Tretorn SERIE+ tournaments, and approximately 150 regular series tournaments, with prize money ranging from $35,000 up to $150,000.
The ATP Challenger Tour was the secondary professional tennis circuit organized by the ATP. The 2012 ATP Challenger Tour calendar comprised 15 top tier Tretorn SERIE+ tournaments, and a total of 148 tournaments, with prize money ranging from $35,000 up to $150,000.
The 2017 ATP World Tour was the global elite men's professional tennis circuit organized by the Association of Tennis Professionals (ATP) for the 2017 tennis season. The 2017 ATP World Tour calendar comprised the Grand Slam tournaments, the ATP World Tour Masters 1000, the ATP Finals, the ATP World Tour 500 series, the ATP World Tour 250 series and the Davis Cup. Also included in the 2017 calendar are the Hopman Cup and the Next Gen ATP Finals, which do not distribute ranking points.
The Oracle Challenger Series – Houston is a professional tennis tournament played on hard courts. It is currently part of the ATP Challenger Tour and the Women's Tennis Association (WTA) 125K series. It is held annually in Houston, United States since 2018. The ATP Challenger Tour returned to Houston, Texas for the first time since 2001, with the inaugural Oracle Challenger Series Houston making its debut in November. Held on the campus of Rice University, at the new $9 million George R. Brown Tennis Complex. Houston is will become one of just two U.S. cities to host tournaments on both the ATP World Tour and ATP Challenger Tour, with the ATP World tour tournament being the U.S. Men's Clay Court Championships. The Oracle Challenger Series – Houston is the second stop for the Oracle Challenger Series calendar. The winner of the Oracle Challenger Series earns a wild card into Indian Wells Masters.
The ATP Challenger Series is the second-tier tour for professional tennis organised by the Association of Tennis Professionals (ATP). The 1992 ATP Challenger Series calendar comprised 89 tournaments, with prize money ranging from $25,000 up to $100,000.
The ATP Challenger Series is the second tier tour for professional tennis organised by the Association of Tennis Professionals (ATP). The 1993 ATP Challenger Series calendar comprised 97 tournaments, with prize money ranging from $25,000 up to $100,000.
The ATP Challenger Series is the second tier tour for professional tennis organised by the Association of Tennis Professionals (ATP). The 1995 ATP Challenger Series calendar comprised 86 tournaments, with prize money ranging from $25,000 up to $125,000.
The ATP Challenger Series is the second tier tour for professional tennis organised by the Association of Tennis Professionals (ATP). The 1996 ATP Challenger Series calendar comprised 98 tournaments, with prize money ranging from $25,000 up to $125,000.
The ATP Challenger Series is the second tier tour for professional tennis organised by the Association of Tennis Professionals (ATP). The 1997 ATP Challenger Series calendar comprised 107 tournaments, with prize money ranging from $25,000 up to $125,000.
The ATP Challenger Series is the second tier tour for professional tennis organised by the Association of Tennis Professionals (ATP). The 1998 ATP Challenger Series calendar comprised 114 tournaments, with prize money ranging from $25,000 up to $125,000.
The ATP Challenger Series is the second tier tour for professional tennis organised by the Association of Tennis Professionals (ATP). The 2001 ATP Challenger Series calendar comprised 135 tournaments, with prize money ranging from $25,000 up to $125,000.
The ATP Challenger Series is the second tier tour for professional tennis organised by the Association of Tennis Professionals (ATP). The 2002 ATP Challenger Series calendar comprised 122 tournaments, with prize money ranging from $25,000 up to $150,000.
The ATP Challenger Series is the second tier tour for professional tennis organised by the Association of Tennis Professionals (ATP). The 2005 ATP Challenger Series calendar comprised 150 tournaments, with prize money ranging from $25,000 up to $150,000.
The ATP Challenger Series is the second tier tour for professional tennis organised by the Association of Tennis Professionals (ATP). The 2006 ATP Challenger Series calendar comprised 161 tournaments, with prize money ranging from $25,000 up to $125,000.
The ATP Challenger Series is the second tier tour for professional tennis organised by the Association of Tennis Professionals (ATP). The 2007 ATP Challenger Series calendar comprised 174 tournaments, with prize money ranging from $25,000 up to $150,000.
Brazil 
Federico Browne 
Rogier Wassen 
Germany 
Karol Beck 
Simon Aspelin 
United States 
Mario Ančić 
Aleksandar Kitinov 
Poland 
Petr Luxa 
Yugoslavia 
Jordan Kerr 
France 
Rik de Voest 
Great Britain 
Daniele Bracciali 
Jonathan Erlich 
Julian Knowle 
Japan 
Vietnam 
Ecuador 
Álex López Morón 
Bermuda 
Mark Merklein 
Mexico 
Dick Norman 
Frédéric Niemeyer 
India 
Ivo Heuberger 
Radoslav Lukaev 
Dmitry Vlasov 
Uzbekistan 
Tuomas Ketola 
Aisam-ul-Haq Qureshi 
Hungary 
Slovenia 
Danai Udomchoke 
Janko Tipsarević 
Ramón Delgado 
Ukraine 
Irakli Labadze 
Lu Yen-hsun 
New Caledonia