2017 Northern Ireland Assembly election

The 2017 Northern Ireland Assembly election was held on Thursday, 2 March 2017. The election was held to elect members (MLAs) following the resignation of deputy First Minister Martin McGuinness in protest over the Renewable Heat Incentive scandal. McGuinness' position was not filled, and thus by law his resignation triggered an election.

Eight parties elected MLAs in the sixth assembly: the Democratic Unionist Party (DUP), Sinn Féin, the Ulster Unionist Party (UUP), the Social Democratic and Labour Party (SDLP), the Alliance Party of Northern Ireland, the Greens, People Before Profit (PBP), and Traditional Unionist Voice (TUV). There was also one Independent Unionist MLA.

It was the sixth election since the Assembly was re-established in 1998, and the first to implement a reduction in size to 90 MLAs (versus the previous 108).

1,254,709 people were registered to vote in the election (26,886 fewer, or a 2.1% decrease, compared to the 2016 Assembly election). 64.78% of registered voters turned out to vote in the 2017 Assembly election, up 9.8 percentage points from the previous Assembly election held in 2016, but 5 percentage points less than in the first election to the Assembly held in 1998.

Theresa Villiers, Secretary of State for Northern Ireland, announced in 2013 that the next Assembly election would be postponed to May 2016, and would be held at fixed intervals of five years thereafter. Section 7 of the Northern Ireland (Miscellaneous Provisions) Act 2014 specifies that elections will be held on the first Thursday in May in the fifth calendar year following that in which its predecessor was elected, which after 2016 was to be 6 May 2021. However, by virtue of section 31(1) of the Northern Ireland Act 1998, there are several circumstances in which the Assembly can be dissolved before the date scheduled.

Martin McGuinness (Sinn Féin), the deputy First Minister, resigned on 9 January 2017 in protest at the Renewable Heat Incentive scandal (RHI) and other issues, such as the DUP's failure to support funding for inquests into killings during The Troubles and for an Irish language project. The First Minister, Arlene Foster (DUP), had been in charge of the RHI scheme in her previous ministerial position, but had refused to temporarily stand down as First Minister while an enquiry took place. Under the power-sharing arrangement, McGuinness' resignation as deputy First Minister meant that Foster automatically lost office as First Minister. The DUP condemned his resignation.

Sinn Féin had seven days, until 5 pm on 16 January 2017, in which to nominate a new deputy First Minister, but refused to do so in the Assembly plenary on 16 January. As a result, the Secretary of State for Northern Ireland, James Brokenshire, confirmed the same day that a snap election would be held on 2 March.

McGuinness subsequently announced that, owing to ill-health, he would not be seeking re-election to the Assembly; he then stepped down from leading the Sinn Féin group. He was replaced by Michelle O'Neill as leader of Sinn Féin in the Northern Ireland Assembly. Nineteen days after the election, McGuinness died.