An election to the 58th Parliament of the United Kingdom for the constituency area of Arfon, held as part of the general election on 12 December 2019.
Plaid Cymru hold by Hywel Williams with a majority of 2,781 - 9.6% - on a turnout of 68.9%.
Candidates
| Name | Party | Vote | Vote share | Vote change |
| WILLIAMS, Hywel | PC | 13,134 | 45.2% | 4.3% |
| WILLIAMS ROBERTS, Steffie | Lab | 10,353 | 35.6% | -4.9% |
| DANIELS, Gonul | Con | 4,428 | 15.2% | -1.1% |
| GRIBBEN, Gary | BRX | 1,159 | 4.0% | - |
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 42,215, having a valid vote count of 29,074 and an invalid vote count of 92.
Result declared at 01:55 on 13 December 2019.