Keith Buchanan (born 11 May 1973) is a Democratic Unionist Party (DUP) politician who has been a Member of the Northern Ireland Assembly (MLA) for Mid Ulster since 2016. He serves as the party's Chief Whip in the Northern Ireland Assembly as well as its spokesperson for Cultural Development and Loyal Order and Groups Engagement.

Buchanan unsuccessfully stood as a Democratic Unionist Party (DUP) candidate at the 2014 Mid Ulster District Council election in the Torrent district.

Buchanan later stood at the 2016 Northern Ireland Assembly election, in which he was a candidate for Mid Ulster. He was the last candidate elected in the constituency, unseating incumbent MLA, and Buchanan's running mate, Ian McCrea.

Buchanan was re-elected at the March 2017 Assembly election, taking 9,568 first-preferences (19.3%). Notably, he became the only unionist candidate to be returned in Mid Ulster, following a reduction in the number of MLAs in each constituency, leading to the Ulster Unionists' Sandra Overend losing her seat.

Buchanan contested Mid Ulster at the June 2017 general election, where he came a distant second to Sinn Féin’s Francie Molloy, with 12,565 votes (26.9%).

At the 2019 general election, Buchanan again finished second to Molloy, though his share of the vote dropped by 2.4%.

In November 2021, Buchanan was called "disgraceful" by a fellow MLA for attempting to link the Gaelic Athletic Association to dissident Irish republicans. SDLP MLA Justin McNulty accused Buchanan of "stirring up the pot of sectarian tensions".

At the 2022 Assembly election, he was the fourth candidate returned in Mid Ulster, and received 16.5% of first-preferences.