1965–66 Birmingham City F.C. season

{{Infobox football club season }} The 1965–66 Football League season was Birmingham City Football Club's 63rd in the Football League and their 25th in the Second Division, to which they were relegated in 1964–65. Having persuaded former Wolverhampton Wanderers manager Stan Cullis out of retirement as successor to Joe Mallett, who remained with the club as Cullis's assistant, they finished in tenth position in the 22-team division. They entered the 1965–66 FA Cup in the third round proper and lost to Leicester City in the fourth, and were beaten in their opening second-round match in the League Cup by Mansfield Town.
 * club              = Birmingham City F.C.
 * season            = 1965–66
 * manager           = {{ublist|Joe Mallett|{{nowrap|(until December 1966}}}|Stan Cullis}}
 * chairman          = Clifford Coombs
 * stdtitle          = Ground
 * stadium           = St Andrew's
 * league            = Football League Second Division
 * league result     = 10th
 * cup1              = FA Cup
 * cup1 result       = Fourth round (eliminated by Leicester City)
 * cup2              = Football League Cup
 * cup2 result       = Second round (eliminated by Mansfield Town)
 * league topscorer  = Geoff Vowden (21)
 * season topscorer  = Geoff Vowden (23)
 * highest attendance = 46,680 vs Leicester City, FA Cup 4th round 12 February 1966
 * lowest attendance = 7,597 vs Leyton Orient, 8 September 1965
 * average attendance = 14,398
 * pattern_la1       = _whiteborder
 * pattern_b1        = _whitecollar
 * pattern_ra1       = _whiteborder
 * pattern_sh1       = _whitesides
 * pattern_so1       =
 * leftarm1          = 000099
 * body1             = 000099
 * rightarm1         = 000099
 * shorts1           = 000099
 * socks1            = ffffff
 * prevseason        = 1964–65
 * nextseason        = 1966–67

Twenty-two players made at least one appearance in nationally organised first-team competition, and there were thirteen different goalscorers. Forward Alec Jackson played in all but two of the team's 45 matches, and Geoff Vowden finished as leading scorer with 23 goals, of which 21 came in league competition.

This season saw the introduction of substitutes into the Football League. In the third game of the season, away to Preston North End on 26 August, Brian Sharples replaced the injured Ron Wylie to become Birmingham's first Football League substitute.

Appearances and goals

 * Numbers in parentheses denote appearances made as a substitute.
 * Players marked † left the club during the playing season.
 * Key to positions: GK – Goalkeeper; FB – Full back; HB – Half back; FW – Forward