An election to the 57th Parliament of the United Kingdom for the constituency area of Lagan Valley, held as part of the general election on 8 June 2017.
DUP hold by Jeffrey M. Donaldson with a majority of 19,229 - 42.8% - on a turnout of 62.1%.
Candidates
| Name | Party | Vote | Vote share | Vote change |
| DONALDSON, Jeffrey M. | DUP | 26,762 | 59.6% | 11.7% |
| BUTLER, Robbie | UUP | 7,533 | 16.8% | 1.6% |
| MCINTYRE, Aaron | APNI | 4,996 | 11.1% | -2.8% |
| CATNEY, Pat | SDLP | 3,384 | 7.5% | 1.3% |
| RUSSELL, Jacqui | SF | 1,567 | 3.5% | 0.6% |
| NICKELS, Ian | Con | 462 | 1.0% | -0.6% |
| ORR, Jonny | Ind | 222 | 0.5% | - |
Under section 13(b) of the Representation of the People Act 1985, a candidate gaining 5% or less of the vote share will forfeit their deposit.
An electorate of 72,380, having a valid vote count of 44,926 and an invalid vote count of 118.
Result declared at 01:29 on 9 June 2017.