| Election Name: | 1986 North Antrim by-election |
| Type: | parliamentary |
| Country: | United Kingdom |
| Ongoing: | no |
| Previous Election: | 1983 United Kingdom general election |
| Previous Year: | 1983 |
| Election Date: | 23 Jan 1986 |
| Candidate1: | Ian Paisley |
| Party1: | Democratic Unionist Party |
| Popular Vote1: | 33,937 |
| Percentage1: | 97.4 |
| Swing1: | 43.2% |
| MP | |
| Posttitle: | Subsequent MP |
| Before Party: | Democratic Unionist Party |
| After Party: | Democratic Unionist Party |
| Turnout: | 53.5% (16.3%) |
| Next Election: | 1987 United Kingdom general election |
| Next Year: | 1987 |
The 1986 North Antrim by-election was one of the fifteen 1986 Northern Ireland by-elections held on 23 January 1986, to fill vacancies in the Parliament of the United Kingdom caused by the resignation in December 1985 of all sitting Unionist Members of Parliament (MPs). The MPs, from the Ulster Unionist Party, Democratic Unionist Party and Ulster Popular Unionist Party, did this to highlight their opposition to the Anglo-Irish Agreement. Each of their parties agreed not to contest seats previously held by the others, and each outgoing MP stood for re-election.
All but one of the Unionists were re-elected, many with extremely large majorities. The largest of all went to Ian Paisley in North Antrim. He won 97.4% of the vote, the highest percentage polled by any candidate in a UK by-election since the 1940 Middleton and Prestwich by-election.