The Speaker of the House of Commons is a very important job.
John Bercow said he'd stand down at the next general election, and since that's just been voted for, he's leaving the job.
Mr Bercow has been a controversial figure, especially over Brexit.
He has often spoken about his job being to make sure MPs have a voice and has used old parliamentary rules to allow MPs to challenge the government's plans.
The speaker is supposed to be the referee in Parliament and not to take sides, but some MPs think he hasn't stuck closely enough to those rules and has made things difficult for the government.
He has been praised by many people for making the hours and working conditions at the Houses of Parliament more family-friendly, although he has also been accused of not doing enough about bullying in the Houses of Parliament.
Read on to find out more about the job of Speaker of the House of Commons.
The Speaker of the House of Commons is one of the biggest jobs in British politics.
He or she chairs debates between Members of Parliament (MPs). They keep order and call up MPs to speak.
They also represent the House of Commons to the Queen, the House of Lords and other authorities, and have three deputies.
The role of the Speaker goes to an MP who is decided in a secret vote of their fellow MPs.
They are elected on the first day a new Parliament comes together or after a Speaker has resigned.
The Speaker must remain impartial at all times. That means they cannot take sides.
When elected, they must resign from their political party and stay separate from political issues - even after they retire.
The Speaker has a powerful role in the House of Commons.
They can ask an MP to withdraw remarks if they think it's inappropriate and tell MPs to be quiet so opinions can be heard.
They can suspend MPs who misbehave and even call off a debating session if things get really out of hand.
They can also choose which amendments can be debated in the House of Commons.
Debates in the House of Commons can get very heated - especially during Prime Minister's Questions (PMQs), which is when the prime minister answers questions from MPs on Wednesdays.
MPs will often shout and jeer at each other and call each other names. You can watch the current speaker tell off MPs in this video.
With more than 600 MPs to control, it can be hard work keeping things running smoothly.
John Bercow was elected on 22 June 2009. He was the 157th Speaker of the House of Commons and was elected MP for Buckingham in 1997 as a member of the Conservative Party.
But who will the next one be?
The election for the next Speaker will be held on 4 November.
The list of candidates includes Sir Lindsay Hoyle, Dame Eleanor Laing, Dame Rosie Winterton, Harriet Harman, Chris Bryant, Sir Edward Leigh, Sir Henry Bellingham, Meg Hillier and Shailesh Vara, most of them are long-serving MPs.
Sir Lindsay Hoyle is currently the frontrunner of the race.
The Speaker role is more than 600 years old.
The first Speaker - Sir Thomas Hungerford - was appointed in 1377, but earlier versions of the role date back to 1258.
Until the 17th Century, the Speaker was seen as working for the King or Queen. But the Speaker was often blamed if they brought news from Parliament that the monarch did not like.
Due to this, seven Speakers were executed between 1394 and 1535!