| Season: | 1955–56 |
| Chairman: | Herbert Merrett[1] |
| League Result: | 17th |
| Cup1 Result: | 4th round |
| Cup2 Result: | Winners |
| Average Attendance: | 26,631 |
| Highest Attendance: | 42,546 v Wolverhampton Wanderers 3 September 1955 |
| Lowest Attendance: | 16,086 v Luton Town, 14 April 1956 |
| League Topscorer: | Gerry Hitchens (15) |
| Season Topscorer: | Gerry Hitchens (28) |
| Pattern B1: | _whitecollarplain |
| Pattern Sh1: | _bluesides |
| Pattern So1: | _band_white |
| Body1: | 0000ff |
| Socks1: | 0000ff |
| Nextseason: | 1956–57 |
The 1955–56 season was Cardiff City F.C.'s 29th season in the Football League. They competed in the 22-team Division One, then the first tier of English football, finishing seventeenth.
After beating Leeds United in their first game, Cardiff were eliminated by West Ham United in the fourth round.[2]
Cardiff were drawn against Pembroke Borough in the fifth round for the second time in a row and, after a 2–2 draw, advanced to the sixth round with a 9–0 replay win. Wins over Wrexham and Oswestry Town saw the club reach the final,[3] beating South Wales rivals Swansea Town 3–2,[4] with a brace from Brian Walsh and one goal from John McSeveney winning the trophy for the eighth time in the club's history and their first since 1930.