Donald Young was the defending champion, but did not complete in the Juniors this year.
Daniel Alejandro López and Matteo Trevisan were the defending champions but did not compete in the Juniors this year.
In the Boys' Singles tournament of the 2009 Australian Open, Yuki Bhambri won in the final 6–3, 6–1, against Alexandros Georgoudas.
Hsieh Cheng-peng and Yang Tsung-hua were the defending champions, but only Cheng-peng participated this year. He partnered with Francis Casey Alcantara and won the final 6–4, 6–2, over Mikhail Biryukov and Yasutaka Uchiyama.
Yang Tsung-hua was the defending champion, but did not compete in the Juniors this year.
Serena and Venus Williams successfully defended their title, defeating Samantha Stosur and Rennae Stubbs in the final, 7–6(7–4), 6–4 to win the ladies' doubles tennis title at the 2009 Wimbledon Championships. As with the previous year, the Williams sisters won the title without dropping a set the entire tournament.
Bob Bryan and Samantha Stosur were the defending champions but lost in the quarterfinals to Mark Knowles and Anna-Lena Grönefeld.
Grigor Dimitrov was the defending champion, but did not complete in the Juniors this year.
Hsieh Cheng-peng is an inactive tennis player from Taiwan. Alongside Yang Tsung-hua he won the 2008 Wimbledon Championships - Boys' Doubles title. He won the 2009 US Open - Boys' Doubles with Márton Fucsovics, as well as the 2008 Australian Open - Boys' Doubles title with Yang Tsung-hua and the 2009 Australian Open - Boys' Doubles title with Francis Casey Alcantara.
Niki Moser and Cedrik-Marcel Stebe were the defending champions, but they did not compete in the Juniors this year.
Yang Tsung-hua is a Taiwanese professional tennis player. On the junior circuit, Yang reached a career-high combined ranking of No. 1 in 2008, when he won the French Open singles title against Polish player Jerzy Janowicz in two sets, and the Australian Open and Wimbledon doubles titles alongside Hsieh Cheng-peng.
Márton Fucsovics and Hsieh Cheng-peng were the defending champions, but Hsieh did not enter the junior competition this year.
Fucsovics played alongside Máté Zsiga, but they lost to Guilherme Clézar and Tiago Fernandes in the second round.
Duilio Beretta and Roberto Quiroz won their second Grand Slam Boys' Doubles title in the year after winning at the French Open. They defeated Oliver Golding and Jiří Veselý 6–1, 7–5 in the final.
George Morgan and Mate Pavić were the defending champions but were no longer eligible to compete as Juniors.
Andrew Harris and Nick Kyrgios were the defending champions, but Harris was no longer eligible to compete in junior tennis, and thus could not defend his title.
Serena and Venus Williams were the defending champions, but could not defend after Venus withdrew with a back injury before the start of competition.
Hsieh Su-wei and Peng Shuai were the defending champions, but lost in the third round to Tímea Babos and Kristina Mladenovic.
Chen Ti and Peng Hsien-yin are the defending champions, but only Chen defended his title partnering Huang Liang-chi.
Ekaterina Makarova and Elena Vesnina were the defending champions, but Vesnina was unable to compete due to an injury. Makarova played alongside Vera Zvonareva, but lost in the second round to Elise Mertens and Demi Schuurs.
Gisela Dulko and Ashley Harkleroad were the defending champions, but they did not compete in the Juniors this year.
Defending champion Hsieh Su-wei and her partner, Elise Mertens, defeated Veronika Kudermetova and Elena Vesnina in the final, 3–6, 7–5, 9–7, to win the Ladies' Doubles tennis title at the 2021 Wimbledon Championships. The pair saved two championship points in the final en route to winning their first major together.
Pierre-Hugues Herbert 
Kevin Krawietz 
