1923–24 Cardiff City F.C. season

The 1923–24 season was the 23rd season of competitive football played by Cardiff City F.C. and the team's third consecutive season in the First Division of the Football League. Cardiff had been promoted to the First Division in the 1920–21 season after finishing as runners-up in the Second Division.

Cardiff played a much improved campaign from the previous season and led the First Division for the majority of the season. A poor run of form in March resulted in the team dropping to fourth position but they recovered to again lead the division prior to the final game of the season. Needing a win to claim the First Division title, Cardiff could only achieve a draw against Birmingham allowing Huddersfield Town to move into first place and win the championship on goal average. The margin of victory, 0.024 of a goal, remains the narrowest title win in the history of the top tier in English football and was the first time the championship had ever been decided by the method. In cup competitions, the side were eliminated in the fourth round of both the FA Cup and Welsh Cup by Manchester City and Newport County respectively. In the Welsh Cup, Cardiff and Newport required four matches to decide a winner of the tie.

Jimmy Nelson made 53 appearances in all competitions, the most of any Cardiff player. He missed a single senior match during the season, a Welsh Cup tie against Newport County. Cardiff used 24 players during the campaign. Len Davies finished the campaign as the club's top goalscorer for the fourth consecutive season, netting 24 goals in all competitions.