Starting from the 2015 season, it was announced that the J.League would again change back to a two-stage "mini-league" (last held in 2004). The winners of each stage and top three clubs of the aggregate table subsequently qualify for the Championship.
Updated to match(es) played on 27 June 2015. Source: Meiji Yasuda J1 League Standings Rules for classification: 1) Points; 2) Goal difference; 3) Goals scored
Updated to match(es) played on 22 November 2015. Source: Meiji Yasuda J1 League 2nd Stage Standings Rules for classification: 1) Points; 2) Goal difference; 3) Goals scored
Updated to match(es) played on 28 November 2015. Source: Meiji Yasuda J1 League Standings Rules for classification: 1) Points; 2) Goal difference; 3) Goals scored Notes:
Gamba's 3rd-place finish in the overall standings for J.League 1 in 2015 saw them paired against the Urawa Red Diamonds at the semi-final stage. Due to Urawa's higher placing, the match was played at Saitama Stadium 2002, Urawa's home ground. A 3–1 win after extra-time set up a two-legged final against Sanfrecce Hiroshima.
= Substitute on, = Substitute Off, = Number of goals scored, = Yellow Card and = Red Card.
AFC Champions League
As 2014 J.League Division 1 champions, Gamba qualified for the 2015 AFC Champions League. This was their 7th appearance in the competition and their first since 2012. They were drawn into Group F along with Buriram United of Thailand, Guangzhou R&F of China and Seongnam of South Korea.[7] Gamba finished top of the group and along with Seongnam qualified for the Round of 16. As Group F winners they were paired against the runner-up of Group H who were FC Seoul. Gamba defeated Seoul 6–3 on aggregate and were paired with yet another Korean side, Jeonbuk Hyundai Motors in the quarter-finals. Following a scoreless draw in the first leg in Korea, Gamba sealed a dramatic 3–2 victory at home, with defender Koki Yonekura netting the winner in the 93rd minute to ensure their progression to the semi-finals where they were paired with Chinese side Guangzhou Evergrande. A 2–1 defeat in China followed by 0–0 draw at home saw Gamba fall at the semi-final stage.
As a result of their qualification for the AFC Champions League, Gamba were given a bye into the quarter-finals of the League Cup, where they were paired against Nagoya Grampus in a two-legged encounter. After a dramatic 10–9 penalty shoot-out victory over Nagoya, in which goalkeeper Yosuke Fujigaya struck the winning penalty, Gamba were drawn against Albirex Niigata in the semi-finals. A 3–2 aggregate win over Niigata set up a final against Kashima Antlers which they lost 3–0.
= Substitute on, = Substitute Off, = Number of goals scored, = Yellow Card and = Red Card.
Emperor's Cup
Due to their success in reaching the AFC Champions League semi-final, Gamba were given a bye to the 4th round of the Emperor's Cup where they were drawn away to fellow J-League 1 side Kawasaki Frontale. A 2–0 victory saw them progress to the quarter-finals where they were paired with another J-League 1 outfit, this time Sagan Tosu. A 3–1 win ensured they qualified for the semi-finals where they were again successful, this time beating 2015 J-League 1 Champions Sanfrecce Hiroshima 3–0 in a match played at Nagai Stadium. The final was played at Ajinomoto Stadium, Tokyo on 1 January 2016 and saw Gamba triumph 2–1 against the Urawa Red Diamonds to retain the trophy.