The MPs are demanding a "meaningful vote" on the final divorce deal, which would force the Prime Minister back to the negotiating table if Parliament is not pleased.
Despite the Government surviving every attempt to amend its EU Withdrawal Bill so far, Wednesday night's crunch debate could see the greatest number of Tory MPs swing against their leader.
Here is who they are:
:: Dominic Grieve
Mr Grieve is the backbencher behind the amendment. A Remain voter in the EU referendum, he says that MPs must sign off on the final deal for parliamentary sovereignty to be truly upheld.
The MP for Beaconsfield has been in the Commons since 1997, serving as Attorney General for four years in David Cameron's government.
Of Wednesday's vote, he says: "The Government has turned this into a battle of wills and that is a completely pointless exercise. They need to listen to the point that's being made and they need to respond to it."
:: Anna Soubry
A former business minister, Ms Soubry has been one of the most outspoken Remain-supporting Tories. She backs staying in the EU single market and customs union.
The Broxtowe MP has backed several amendments to the Brexit bill already, and warned that without accepting the latest one, Parliament will be "effectively a rubber stamp on a done deal".
:: Antoinette Sandbach
Ms Sandbach was among the MPs branded "Brexit mutineers" by the Daily Telegraph for her votes in Parliament on Brexit.
She has only been MP for Eddisbury for two years, but has already made her mark on Parliament, sitting on the energy, Welsh affairs and business strategy committees.
Of the "meaningful vote" debate, Ms Sandbach says: "I don't want the Government to push it to a vote, I would like them to accept that amendment."
She added: "Taking back control was taking back control to Parliament and not to the executive, to government."
:: George Freeman
Mr Freeman is another of the newer intake of MPs, winning the contest to represent Mid Norfolk in 2010.
He served as life sciences minister for two years, but returned to the backbenches after the EU referendum. He backed Remain.
Agreeing with Ms Sandbach's comments, he said on Monday: "Brexit was supposed to be about restoring democratic authority and accountability to our Parliament. Starting with the Brexit Bill."
:: Heidi Allen
An outspoken presence in Parliament since she joined it in 2015, Ms Allen said on Wednesday morning that "I and 64 colleagues have backed Dominic Grieve's amendment".
The South Cambridgshire MP has tackled the Government previously on universal credit and child tax credit cuts.
She says denying Parliament a meaningful vote on the Brexit deal "would be an affront to the system of democracy we have to proudly exported all over the world".