The second elections to the Northern Ireland Assembly, which at the time of the elections had been suspended for just over a year, were held on Wednesday 26 November 2003. Six members were elected by Single Transferable Vote from each of Northern Ireland's eighteen Westminster Parliamentary constituencies, giving a total of 108 MLAs, or Members of the Legislative Assembly. The elections were contested by 18 parties, and a number of independent candidates.
On the unionist side, the Democratic Unionist Party gained ten seats, primarily at the expense of smaller Unionist parties, to become the largest party both in seats and votes. Despite slipping to third place in first preference votes the Ulster Unionist Party actually increased their vote slightly and had a net loss of only one seat. Shortly after the election three Ulster Unionist MLAs, Jeffrey Donaldson, Nora Beare and Arlene Foster, defected to the Democratic Unionists.
Several sitting MLAs stood under a different label to the one they had used in 1998. Some had failed to be selected by their parties to stand and so stood as independents, whilst others had changed parties during the course of the assembly. Most of these realignments occurred within the unionist parties, with several defections between existing parties and two new parties being formed - the United Unionist Coalition (formed by the three MLAs elected as independent unionists, though one later joined the Democratic Unionist Party) and the Northern Ireland Unionist Party (formed by four of the five MLAs elected as the UK Unionist Party, though one later left them, joined the Democratic Unionists for a period but contested the election as an independent unionist). Neither the United Unionist Assembly Party nor the Northern Ireland Unionists won any seats in the 2003 election.