Gianluigi Quinzi (Italian pronunciation: [dʒanluˈiːdʒi ˈkwintsi]; born 1 February 1996), is an Italian tennis coach and former tennis player. He reached his career-high singles ranking of world No. 142 rankings in 2019. He reached his career high ranking of No. 1 in ITF Juniors rankings on 1 January 2013, for a week.

Quinzi won the 2013 Wimbledon Championships Junior Boys' singles title, defeating in the final Chung Hyeon.

Gianluigi was born in Cittadella on 1 February 1996 and grew up in Porto San Giorgio with his mother Carlotta, a ski racer and handball player, and his father Luca, the president of a local tennis club.

Initially Quinzi applied himself to Alpine skiing, gaining a second place in the championships of the Trentino-Alto Adige; but at seven years old, after leaving other sports as well, he focused his efforts primarily on tennis.
At the age of 8 he was admitted to the academy of the talent scout Nick Bollettieri and he moved to Florida with his mother and little brother. In the same year he won at the Little Mo, tournament played in Florida which is reserved for Under-10 players. At thirteen years old, he became the youngest player in the ITF Junior rankings and the next year he triumphed in four tournaments in a row with a series of twenty victories.

gedfourteen – in 2010 – he won the Honduras Junior Bowl, on clay court, by defeating in the final Walner Espinoza, becoming the youngest Italian player to win an ITF Junior tournament. With the results obtained in 2010, Quinzi was nominated Player of the Year, in the category Under-14, by the European Tennis Association.

Quinzi obtained his best result in Italy: in Milan he won the Trofeo Bonfiglio in 2012, beating Temür Ismailov in three sets. At the 2012 French Open Junior he was seeded No. 2. He was eliminated in the third round by British tennis player Kyle Edmund. At the 2012 Wimbledon Junior the young Italian, No. 3 seed, arrived in the semifinals where he lost to Luke Saville, who was No. 1 in the Junior ITF rankings and the returning champion from 2011. In September, he reached the 2012 US Open Junior quarterfinals, losing in three sets to the Japanese player Yoshihito Nishioka.

In September 2012, Quinzi won the 2012 Junior Davis Cup with Filippo Baldi: is the first time that Italy won the Junior Davis Cup, after the 2011 Italy finished runner-up with Quinzi also playing.

On 1 January 2013, Quinzi reached his best ranking of No. 1 in the world in the ITF Junior rankings, and he is the first Italian player ever to obtain this result, but it drops to second place after just one week. At 2013 Australian Open Quinzi, seeded No. 2, reached the quarterfinals, but there he was defeated by Thanasi Kokkinakis in three sets. In March, Quinzi reached the final of Banana Bowl tournament; he lost in three sets to the French player Jean Sebastien Tatlot. The following week he won Copa Gerdau beating Stefan Kozlov in the final.