The 2008–09 Spartan South Midlands Football League season is the 12th in the history of Spartan South Midlands Football League a football competition in England.
| Competition: | Spartan South Midlands Football League Premier Division |
| Season: | 2008–09 |
| Winners: | Biggleswade Town |
| Promoted: | Biggleswade Town |
| Relegated: | Cockfosters Holmer Green |
| Matches: | 420 |
| Total Goals: | 1480 |
| Prevseason: | 2007–08 |
| Nextseason: | 2009–10 |
The Premier Division featured 19 clubs which competed in the division last season, along with three new clubs:
| Competition: | Spartan South Midlands Football League Division One |
| Season: | 2008–09 |
| Winners: | Royston Town |
| Promoted: | Royston Town Hatfield Town |
| Matches: | 420 |
| Total Goals: | 1584 |
| Prevseason: | 2007–08 |
| Nextseason: | 2009–10 |
Division One featured 16 clubs which competed in the division last season, along with five new clubs.
Also, Ruislip Manor changed name to Tokyngton Manor.
| Competition: | Spartan South Midlands Football League Division Two |
| Season: | 2008–09 |
| Winners: | The 61 |
| Promoted: | Hadley AFC Dunstable |
| Matches: | 272 |
| Total Goals: | 1078 |
| Prevseason: | 2007–08 |
| Nextseason: | 2009–10 |
Division Two featured 13 clubs, which competed in the division last season, along with five new clubs: