Nine candidates are running to replace him, including politicians from Labour, the Liberal Democrats, and the Conservative Party.
By-elections take place between general elections for a number of reasons, such as when an MP resigns, dies, is declared bankrupt, is convicted of a serious criminal offence or takes a seat in the House of Lords.
When the seat is vacant, an MP from the same party from a neighbouring constituency manages constituency matters.
When is the Chester by-election?
The Chester by-election is taking place on December 1.
Why is there a Chester by-election?
The seat became available after two allegations of sexual misconduct made against Mr Matheson by a former member of staff were upheld by a parliamentary watchdog.
The Labour MP, who denied the allegations, subsequently resigned.
The Independent Expert Panel found that Mr Matheson had invited the former employee on a private trip abroad and “the invitation was sexually motivated, unwanted, and had placed the complainant under pressure and intimidated her”. It then recommended that Mr Matheson be suspended from Parliament for four weeks.
Instead choosing to stand down, Mr Matheson said in his resignation statement that he was “dismayed that [he had] been found guilty of several allegations that [he knows] to be untrue”. He added: “I believe that the honourable and right thing to do now is to resign my seat and seek to rebuild my life elsewhere.”
Who is running to be MP in Chester?
There are nine people running for MP in the Chester by-election: Jeanie Barton for Reform UK, Paul Bowers for the Green Party, Samantha Dixon for the Labour Party and Cain Griffiths for UKIP.
Rob Herd is running for the Liberal Democrats, Richard Hewison for the Rejoin EU party and Liz Wardlaw is the Conservative candidate.
Additionally, Howling Hope is standing for the Official Monster Raving Loony Party and Chris Quartermaine is running on behalf of the Freedom Alliance.
The City of Chester is considered a Labour stronghold, with its constituents voting Labour since 2015.
In 2019, Mr Matheson and Labour won 49.6 per cent of the vote, while the Conservatives won 38.3 per cent.