After days of debate, they will vote on both the withdrawal agreement, a legally-binding, nearly 600 page document that sets out how the UK leaves the European Union, and the future political framework — a set of ambitions for a European Union (EU)-UK trade deal.
Adding pressure to the mix, it follows a week of Brexit defeats for May after MPs voted last Wednesday in favour of a limited period to present next steps on Brexit if the current deal is rebuffed.
Had the vote on May's deal taken place when it was originally planned back in December, the government would have 21 days to return to the Commons to set out what it plans to do next, in the event of a deal rejection.
But now, May would be given just three days to present a Brexit plan B.
What are the possible outcomes of the vote?
Find out here: bit.ly/2VTseP7
What are the top stories today? Click to watch: https://www.youtube.com/user/Euronews/videos
Euronews: the most watched news channel in Europe
Euronews is available in 12 languages: https://www.youtube.com/user/euronewsnetwork/channels