An election to the 57th Parliament of the United Kingdom for the constituency area of Harrow West, held as part of the general election on 8 June 2017.
Labour hold by Gareth Thomas with a majority of 13,314 - 26.4% - on a turnout of 72.1%.
Candidates
| Name | Party | Vote | Vote share | Vote change |
| THOMAS, Gareth | Lab / Co-op | 30,640 | 60.8% | 13.9% |
| DAVID, Hannah | Con | 17,326 | 34.4% | -7.8% |
| NOYCE, Christopher | LD | 1,267 | 2.5% | -0.8% |
| LANGLEY, Rowan | Green | 652 | 1.3% | -1.5% |
| ALAGARATNAM, Rathy | UKIP | 470 | 0.9% | -3.5% |
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 69,797, having a valid vote count of 50,355 and an invalid vote count of 128.
Result declared at 03:25 on 9 June 2017.