2023–24 Bayer 04 Leverkusen season

The 2023–24 season was Bayer 04 Leverkusen's 120th season in existence and 45th consecutive season in the Bundesliga. They also competed in the DFB-Pokal and the UEFA Europa League.

Following a 5–0 victory over Werder Bremen on 14 April 2024, Bayer Leverkusen won the Bundesliga title for the first time in the club's history. It also marked the club's first major trophy since 1993. In addition, they became the first team in history to win the Bundesliga without losing a single match, finishing the competition with 28 wins and 6 draws.

On 9 May 2024, following a 2–2 draw against Roma in the Europa League semi-final second leg, the club set a new European record for consecutive competitive matches without a loss (49), breaking Benfica's record of 48 games unbeaten set between 1963 and 1965. In the pursuit of achieving this record, the club succeeded in netting 17 goals during stoppage time and 34 goals from the 80th minute onwards, encompassing crucial last-minute match winners or equalizers. However, Leverkusen's unbeaten run would end at 51 matches, following a 3–0 defeat to Atalanta in the Europa League final on 22 May.

On 25 May, Leverkusen won the DFB-Pokal final against Kaiserslautern and completed an undefeated domestic double, finishing their campaign with just one defeat in 53 competitive matches.