An election to the 57th Parliament of the United Kingdom for the constituency area of Portsmouth South, held as part of the general election on 8 June 2017.
Labour gain from Conservatives by Stephen Morgan with a majority of 1,554 - 3.5% - on a turnout of 63.9%.
Candidates
| Name | Party | Vote | Vote share | Vote change |
| MORGAN, Stephen | Lab | 18,290 | 41.0% | 21.5% |
| DRUMMOND, Flick | Con | 16,736 | 37.6% | 2.7% |
| VERNON-JACKSON, Robert | LD | 7,699 | 17.3% | -5.0% |
| CHIPPINDALL-HIGGIN, Kevan | UKIP | 1,129 | 2.5% | -10.8% |
| MCCULLOCH, Ian | Green | 712 | 1.6% | -5.9% |
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 69,785, having a valid vote count of 44,566 and an invalid vote count of 94.
Result declared at 03:25 on 9 June 2017.