Sousa began the 2015 season with an early round loss at the Auckland Open.
At the 2015 Australian Open, he started his campaign with wins over wild card Jordan Thompson and Martin Kližan.
He progressed to a third round match-up with 6th seed Andy Murray, becoming the second Portuguese player to reach that stage.
Sousa lost in straight sets to Murray.
In the doubles competition, Sousa partnered with Santiago Giraldo to reach the second round, where they lost to 2nd seeds Julien Benneteau and Édouard Roger-Vasselin.
In February, Sousa participated at the Open Sud de France.
After defeating Philipp Kohlschreiber in the quarterfinals, he lost in the semifinals to Jerzy Janowicz in three sets.
After early round losses at the Rotterdam Open and Open 13, Sousa reached the second round of the Dubai Tennis Championships, where he was beaten by Murray.
Sousa was then called for the Davis Cup team to face Morocco for the Europe/Africa Zone's Group II first round in early March.
He won his singles rubber and partnered with Frederico Ferreira Silva to win the doubles rubber and close the tie in Portugal's favour.
After injuring his knee and suffering breathing difficulties, Sousa was eliminated from both Indian Wells Masters and Miami Masters in the first round.
He returned to Barcelona for recovery.

Sousa returned in April at the Monte-Carlo Masters, losing in the second round to Milos Raonic.
At the Barcelona Open and Estoril Open, he lost in early rounds and then was eliminated from the Madrid Masters in the second round by Stan Wawrinka and from the Rome Masters in the first round by John Isner.
At the Geneva Open, Sousa won a first round match over his Brazilian homophone João Souza, which was notable for the umpire needing to refer to each player by their nationality to distinguish between them during the calls.
Sousa proceeded to the final, his first of the season, where he lost to Thomaz Bellucci.
At the French Open, Sousa beat Canadian Vasek Pospisil in straight sets in the first round, and was defeated by 3rd seed Andy Murray in the second round.
In the men's doubles of the tournament, Sousa partnered with Bellucci and was knocked out in the first round by 11th seeds Jamie Murray and John Peers.
In June, Sousa did not have a strong grass court season; he was defeated in the early rounds at the Rosmalen Grass Court Championships, the Queen's Club Championships and the Nottingham Open.
At Wimbledon, Sousa was again eliminated in straight sets in the first round by French Open champion and 4th seed Stan Wawrinka.
His results did not improve in the men's doubles competition, from which he was eliminated in the first round while partnering with Santiago Giraldo.

At the Davis Cup Group II second round against Finland, Sousa rebounded with wins in his two singles rubbers and in the doubles rubber with Gastão Elias.
At the Croatia Open, he beat in succession Andreas Seppi, Fabio Fognini and Roberto Bautista Agut to reach his second final in 2015.
Sousa lost the final to Dominic Thiem.
After a quarterfinal exit at the Swiss Open, He suffered a first-round loss to Bernard Tomic at the Canada Masters and reached the second round at the Cincinnati Masters, where he lost to Marin Čilić.
Following a brief appearance at the Winston-Salem Open, Sousa was defeated at the US Open by Ričardas Berankis in five sets in the first round.
In the men's doubles competition, Sousa became the second Portuguese player to reach the quarterfinals of a Grand Slam event after Nuno Marques, also in men's doubles at the 2000 Australian Open.
Sousa and his partner Argentinian Leonardo Mayer were denied a presence in the semifinals by Americans Sam Querrey and Steve Johnson.

Sousa returned to the Davis Cup in September to help Portugal defeat Belarus and gain promotion to Europe/Africa Zone's Group I in 2016.
Despite losing his first singles rubber, he won the doubles rubber with Elias and the deciding singles rubber against Uladzimir Ignatik.
At the St. Petersburg Open, Sousa reached his third final of the season.
Following wins over Marcel Granollers, Simone
Sousa began the 2015 season with an early round loss at the Auckland Open. At the 2015 Australian Open, he started his campaign with wins over wild card Jordan Thompson and Martin Kližan. He progressed to a third round match-up with 6th seed Andy Murray, becoming the second Portuguese player to reach that stage. Sousa lost in straight sets to Murray. In the doubles competition, Sousa partnered with Santiago Giraldo to reach the second round, where they lost to 2nd seeds Julien Benneteau and Édouard Roger-Vasselin. In February, Sousa participated at the Open Sud de France. After defeating Philipp Kohlschreiber in the quarterfinals, he lost in the semifinals to Jerzy Janowicz in three sets. After early round losses at the Rotterdam Open and Open 13, Sousa reached the second round of the Dubai Tennis Championships, where he was beaten by Murray. Sousa was then called for the Davis Cup team to face Morocco for the Europe/Africa Zone's Group II first round in early March. He won his singles rubber and partnered with Frederico Ferreira Silva to win the doubles rubber and close the tie in Portugal's favour. After injuring his knee and suffering breathing difficulties, Sousa was eliminated from both Indian Wells Masters and Miami Masters in the first round. He returned to Barcelona for recovery.
Sousa returned in April at the Monte-Carlo Masters, losing in the second round to Milos Raonic. At the Barcelona Open and Estoril Open, he lost in early rounds and then was eliminated from the Madrid Masters in the second round by Stan Wawrinka and from the Rome Masters in the first round by John Isner. At the Geneva Open, Sousa won a first round match over his Brazilian homophone João Souza, which was notable for the umpire needing to refer to each player by their nationality to distinguish between them during the calls. Sousa proceeded to the final, his first of the season, where he lost to Thomaz Bellucci. At the French Open, Sousa beat Canadian Vasek Pospisil in straight sets in the first round, and was defeated by 3rd seed Andy Murray in the second round. In the men's doubles of the tournament, Sousa partnered with Bellucci and was knocked out in the first round by 11th seeds Jamie Murray and John Peers. In June, Sousa did not have a strong grass court season; he was defeated in the early rounds at the Rosmalen Grass Court Championships, the Queen's Club Championships and the Nottingham Open. At Wimbledon, Sousa was again eliminated in straight sets in the first round by French Open champion and 4th seed Stan Wawrinka. His results did not improve in the men's doubles competition, from which he was eliminated in the first round while partnering with Santiago Giraldo.
At the Davis Cup Group II second round against Finland, Sousa rebounded with wins in his two singles rubbers and in the doubles rubber with Gastão Elias. At the Croatia Open, he beat in succession Andreas Seppi, Fabio Fognini and Roberto Bautista Agut to reach his second final in 2015. Sousa lost the final to Dominic Thiem. After a quarterfinal exit at the Swiss Open, He suffered a first-round loss to Bernard Tomic at the Canada Masters and reached the second round at the Cincinnati Masters, where he lost to Marin Čilić. Following a brief appearance at the Winston-Salem Open, Sousa was defeated at the US Open by Ričardas Berankis in five sets in the first round. In the men's doubles competition, Sousa became the second Portuguese player to reach the quarterfinals of a Grand Slam event after Nuno Marques, also in men's doubles at the 2000 Australian Open. Sousa and his partner Argentinian Leonardo Mayer were denied a presence in the semifinals by Americans Sam Querrey and Steve Johnson.
Sousa returned to the Davis Cup in September to help Portugal defeat Belarus and gain promotion to Europe/Africa Zone's Group I in 2016. Despite losing his first singles rubber, he won the doubles rubber with Elias and the deciding singles rubber against Uladzimir Ignatik. At the St. Petersburg Open, Sousa reached his third final of the season. Following wins over Marcel Granollers, Simone
João Sousa