An election to the 58th Parliament of the United Kingdom for the constituency area of Gainsborough, held as part of the general election on 12 December 2019.
Conservative hold by Edward Leigh with a majority of 22,967 - 45.0% - on a turnout of 66.9%.
Candidates
| Name | Party | Vote | Vote share | Vote change |
| LEIGH, Edward | Con | 33,893 | 66.4% | 4.6% |
| SMITH, Perry | Lab | 10,926 | 21.4% | -7.3% |
| ROLLINGS, Lesley | LD | 5,157 | 10.1% | 3.0% |
| CAVILL, Mary | Ind | 1,070 | 2.1% | - |
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 76,343, having a valid vote count of 51,046 and an invalid vote count of 259.
Result declared at 03:35 on 13 December 2019.