The 2003–04 Northern Premier League season was the 36th in the history of the Northern Premier League, a football competition in England. Teams were divided into two divisions; the Premier and the First. This season was the last before the formation of the Conference North and the Conference South, so most of the Premier Division teams were promoted to the Conference North for next season. Subsequently, the First Division had most of its teams promoted to the Premier Division, with new teams admitted from the leagues just below the Northern Premier in the English football league system, although the league reform meant that the "promoted" clubs remained in the same tier within the English football league system, and further meant that while there was no relegation within the NPL itself, those clubs that missed out on promotion nevertheless had their position within the league system downgraded by one tier.