The 2017–18 season was Futbol Club Barcelona's 118th in existence and the club's 87th consecutive season in the top flight of Spanish football. This was also the first year under head coach Ernesto Valverde.
The team produced a solid season, clinching the domestic double, going undefeated in the league up until match day 37, where Barça lost to Levante 4–5, and producing an emphatic 5–0 victory over Sevilla in the Copa final. However, in the Champions League, Barcelona crashed out in the quarter-finals for the third year in a row, losing to Roma 0–3 and being eliminated on away goals as a result (after a 4–1 home victory). The season was the first since 2012–13 season without Neymar, who departed to join Paris Saint-Germain.
Season overview
May
On 29 May, the club announced Ernesto Valverde would be the new Barcelona coach following the departure of Luis Enrique at the end of the previous season.
On 29 May, Barcelona and goalkeeper Marc-André ter Stegen negotiated a five-year contract extension lasting until 30 June 2022.
June
On 14 June, Fluminense centre-back Marlon Santos signed a three-year contract.
On 30 June, goalkeeper Jordi Masip's contract expired; he was not resigned and was therefore released.
On 30 June, the club activated a buyback clause for Everton's Gerard Deulofeu.
On 30 June, the club announced they have reached an agreement with Real Betis for the transfer of Cristian Tello for €4 million.
July
On 7 July, Barcelona and Jérémy Mathieu agreed to mutually terminate the defender's contract. Mathieu subsequently joined Portuguese club Sporting CP on a free transfer.
On 13 July, Barcelona and Benfica reached an agreement for the transfer of right-back Nélson Semedo for €30 million.
On 21 July, Barcelona defeated Juventus 2–1 in a pre-season friendly. Neymar notched two impeccable first-half goals as the Catalans rolled past the Italian champions before 82,104 fans at a sold-out MetLife Stadium in the 2017 International Champions Cup. Giorgio Chiellini pulled one back for Juventus in the 63rd minute, not enough to keep the Ernesto Valverde era from beginning with a convincing win.
On 26 July, Barcelona won 1–0 against Manchester United in a pre-season friendly. Neymar scored in the 31st minute.
On 29 July, Barcelona defeated Real Madrid 3–2 in their final match of the U.S. tour, winning the United States edition of the 2017 International Champions Cup. Messi, Ivan Rakitić and Gerard Piqué each scored one goal.
August
On 3 August, Barcelona confirmed the unilateral termination of Neymar's contract as Neymar's legal representatives paid his €222 million buyout clause. In turn, Barcelona announced a turnover of operation details to UEFA so as to allow UEFA to determine any disciplinary responsibilities that may arise. Neymar subsequently joined Paris Saint-Germain on a five-year contract.
On 4 August, Barcelona drew 1–1 with Gimnàstic in a pre-season friendly game in Tarragona. Manu Barreiro put the hosts ahead in the 11th minute only for Paco Alcácer to score the equalizer for the Blaugrana from a free-kick in the 79th minute.
On 7 August, Barcelona defeated Chapecoense 5–0 in the 52nd edition of the Joan Gamper Trophy. Gerard Deulofeu, Sergio Busquets, Messi, Luis Suárez and Denis Suárez were the scorers for Barça; Messi and Deulofeu also assisted two goals each. Busquets was named the Man of the Match.
On 13 August, Barcelona lost 1–3 to Real Madrid in the first leg of the 2017 Supercopa de España. The first half of the match ended goalless. Five minutes into the second half, Marcelo fired a cross that deflected off Piqué's foot, resulting in an own goal. In the 77th minute, Luis Suárez was brought down in the box by goalkeeper Keylor Navas, resulting in a penalty which was converted by Lionel Messi. Messi's hit marked his 25th goal in the fixture. In the 80th minute, Real Madrid scored their second through a counterattack when Isco assisted Cristiano Ronaldo, who shot into the top right corner from the edge of the box. Ronaldo was booked for removing his shirt as part of his celebrations. Two minutes later, he was booked again for a dive in the penalty box, which resulted in a red card and a subsequent suspension for the second leg. Real's last goal was scored in the 90th minute in similar fashion to the second, when Marco Asensio shot into the top left corner following an assist from Lucas Vázquez.
On 14 August, Barcelona announced they had reached an agreement with Guangzhou Evergrande Taobao for the transfer of Paulinho for €40 million. His release clause was set at €120 million.