Local people will go the polls on Thursday, 20 July. The election has been called following the resignation of MP Nigel Adams, who has held the seat since 2010.
Anyone interested in becoming a candidate must submit a completed set of nomination forms before the deadline of 4pm on Friday, 23 June.
The electorate in the Selby and Ainsty constituency have until midnight on Tuesday, 4 July, to register to vote and until 5pm on Wednesday, 5 July, to apply for a postal vote. If someone is unable to vote in person or by post they have until 5pm on Wednesday, 12 July, to apply for a proxy vote.
Voters attending the polling station for the by-election will need to bring photographic identification to be able to vote.
There are many accepted forms of ID including a UK or Northern Ireland photocard driving licence, full or provisional, a UK passport or a passport issued by the EU, Norway, Iceland, Liechtenstein, the Isle of Man, or any of the Channel Islands, and some concessionary travel passes, such as an older person’s bus pass or blue badge. Voters will be able to use expired ID if they are still recognisable from the photo.
Anyone without an accepted form of ID should apply for a free voter authority certificate by 5pm on Wednesday, 12 July.