| League Result: | 20th |
| League Topscorer: | George Johnston (17) |
| Season Topscorer: | George Johnston (23) |
| Cup1 Result: | 4th round |
| Cup2 Result: | Semi-finals |
| Cup3 Result: | 1st round |
| Cup4 Result: | 5th round |
| Average Attendance: | 11,005 |
| Highest Attendance: | 19,827 (v Wolverhampton Wanderers, 4 September 1965) |
| Lowest Attendance: | 5,934 (v Norwich City, 10 May 1966) |
| Pattern La1: | _whiteborder |
| Pattern B1: | _whitecollar |
| Pattern Ra1: | _whiteborder |
| Leftarm1: | 0000ff |
| Body1: | 0000ff |
| Rightarm1: | 0000ff |
| Shorts1: | 0000ff |
| Socks1: | 0000ff |
| Nextseason: | 1966–67 |
The 1965–66 season was Cardiff City F.C.'s 39th season in the Football League. They competed in the 22-team Division Two, then the second tier of English football, finishing twentieth.
The season also saw the club reach the semi-finals of the Football League Cup, the furthest they have ever gone in the competition, before being beaten by West Ham United.