The International Tennis Federation (ITF) designates a World Champion each year based on performances throughout the year, emphasising the Grand Slam tournaments, and also considering team events such as the Davis Cup and Fed Cup. Men's and women's singles champions were first named in 1978; the title is now also awarded for doubles, wheelchair, and junior players.
The ITF's constitution states that no tennis tournament can be designated the "World Championships" without unanimous consent of the ITF Council. There is currently no such tournament. The constitution also states:
The ITF may award the title of World Champion to players who, in the opinion of the Board of Directors, are the most outstanding players in any one-year. The names of players who have been awarded this title shall be listed in the Roll of Honour.
It also states:
Official Tennis Championships [i.e. the Grand Slam events] shall be the decisive factor in the determination of the ITF World Champions for each year.
For singles, ITF appoints a panel of former top players at the start of the season, which votes on the champion at the end of the season.
The boys' and girls' singles and doubles titles prior to 2003 were awarded based on world ranking. Since then singles and doubles rankings have been combined in a single award each for boys and for girls.
The ITF World Champions' Dinner takes place in Paris during the French Open, to honour the previous year's champions, who are presented with a trophy, but not any monetary prize.
The first men's panel in 1978 had three members, Don Budge, Fred Perry, and Lew Hoad, who attended the season's Grand Slam events at ITF expense to inform their choice. The 1983 panel split two to one between John McEnroe (votes of Budge and Perry) and Mats Wilander (vote of Hoad). The 1984 panel had five members, while the 1985 panel had four: Budge, Perry, Hoad, and Tony Trabert. When Ivan Lendl was chosen as champion for 1985, the panel's announcement was accompanied with a rebuke for Lendl's criticism of some tournaments and his refusal to play in the Davis Cup. Perry and Trabert were on the 1986 panel, with performances outside the Grand Slams taken into consideration.
The 1990 designation of Lendl as champion was a surprise. That year, the Association of Tennis Professionals named Stefan Edberg its "Player of The Year", in accordance with the ATP Rankings, while Tennis Magazine (France) ranked Edberg first, Andre Agassi second, and Lendl third. Tennis also suggested the ITF was punishing Edberg for denigrating the Grand Slam Cup tournament it had introduced. The ITF panel, of Perry, Trabert, and Frank Sedgman, called it "the toughest decision any of us can remember having to make", and stated it was Lendl's better average performance in the Grand Slams that made the difference.
Other instances when the ITF choices differed from the ATP rankings are 1978 (Jimmy Connors), 1982 (McEnroe), 1989 (Lendl) and 2013 (Rafael Nadal).
The women's panel initially featured three former women's champions, with Althea Gibson among them through the early 1980s.
ITF world champions for women differed from the WTA year-end rankings the following years: 1978 (Martina Navratilova), 1994 (Steffi Graf), 2001 (Lindsay Davenport), 2004 (Lindsay Davenport), 2005 (Lindsay Davenport), 2011 (Caroline Wozniacki), 2012 (Victoria Azarenka).