| Manager: | Paul Jewell |
| Chairman: | Dave Whelan |
| Stadium: | JJB Stadium |
| League: | Championship |
| League Result: | 2nd (promoted) |
| Cup2: | FA Cup |
| Cup2 Result: | Third round proper |
| Cup3: | League Cup |
| Cup3 Result: | First round |
| League Topscorer: | Nathan Ellington (24) |
| Season Topscorer: | Nathan Ellington (24)[1] |
| Highest Attendance: | 20,745 (vs. Sunderland, 5 April) |
| Lowest Attendance: | 7,547 (vs. Crewe Alexandra, 19 October) |
| Average Attendance: | 11,562[2] |
| Prevseason: | 2003–04 |
| Nextseason: | 2005–06 |
During the 2004–05 English football season, Wigan Athletic F.C. competed in the Football League Championship.
After only 27 years as a Football League club, Wigan Athletic won promotion to English football's top flight for the first time in their history, securing promotion on the final day of the Championship league campaign as runners-up in their division. This was also their highest-ever finish in the Football League in their history. It was also only Wigan's second season in the second tier of the English league, having just missed out on the playoffs a year earlier.
Wigan's league success did not translate to the domestic cup competitions: they only played one match in each cup before being knocked out. This may have turned out to be beneficial to Wigan, as it allowed the club to focus on the league rather than a cup run.
Squad at end of season
| 24 May 2004 | Per Frandsen | Bolton Wanderers | Free | [3] | |
| 16 June 2004 | David Graham | Torquay United | £215,000 | [4] | |
| 28 June 2004 | David Wright | Crewe Alexandra | Undisclosed | [5] | |
| 4 August 2004 | Emerson Thome | Bolton Wanderers | Free | [6] | |
| 15 September 2004 | Gareth Whalley | Cardiff City | Free | [7] | |
| 8 January 2005 | Andreas Johansson | Djurgardens IF | Undisclosed | [8] | |
| 4 March 2005 | Graham Kavanagh | Cardiff City | £400,000 | [9] |
| 26 May 2004 | Jason de Vos | Ipswich Town | Free | [10] | |
| Andy Liddell | Sheffield United | Free | |||
| Peter Kennedy | Peterborough United | ||||
| 9 August 2004 | Tony Dinning | Ipswich Town | Loan | [11] | |
| 6 December 2004 | Tony Dinning | Bristol City | Free | [12] | |
| Michael Flynn | Gillingham | Free | |||
| Neil Roberts | Doncaster Rovers | ||||
| Per Frandsen | None | Retirement |
Considering starts in all competitions[13]
John Filan, 47
Alan Mahon, 23