The 112 names include dozens who have already been MPs, including ex-ministers Margaret Beckett, Maria Eagle and Ben Bradshaw, plus recent Speaker candidate Chris Bryant.
Less experienced MPs include Tulip Siddiq and Rosie Duffield are also on the list, plus more than 15 first-time candidates, suggesting the rebellion goes beyond the Parliamentary party.
Among them is Flo Eshalomi, who looks set to replace the retiring Kate Hoey, a prominent Labour Leave supporter, in the London seat of Vauxhall.
One of the most recent sign-ups was Ealing candidate Rupa Huuq, who last night tweeted the campaign pledge.
Organised by grassroots group Remain Labour, it states: 'Labour is committed to a confirmatory referendum, to give you a final say on Brexit.
'If elected as your Labour MP, I pledge to campaign to Remain in the EU.'
This could put them on a collision path with party leader Jeremy Corbyn.
Former foreign office minister Chris Bryant is among those who have signed the Remain Labour pledge to back remain if there is a second referendum
Canterbury MP Rosie Duffield (left) and Hampstead and Kilburn's Tulip Siddiq are also among those who have put their name to it
Ealing Central and Acton MP Rupa Huq last night signed up to the campaign with a tweet (below)
While he has committed the party to a new vote if it wins power, he will not decide whether his party will officially back Remain or quit under the terms of its own Brexit deal until after the election.
While a second vote would only take place if Boris Johnson is defeated, the move by the backbenchers is a defiant one just weeks before the general election.
Andrew Lewin, founder of Remain Labour, said: 'Remain voters want to vote for the Labour Party with confidence at this election.
'Our pledge will help candidates in England, Scotland and Wales to underline that the Labour Party is the strongest Remain Alliance in the country.'
Dr Rosena Allin-Khan last week hit the streets in her Tooting seat with placards saying 'Vote Rosena, vote Remain' according to photos posted on social media
The NHS medic took over from Sadiq Khan in the south London seat in 2016 after he became London mayor
In comes after a Labour candidate decided to fight the general election campaign as an overt Remain candidate.
Dr Rosena Allin-Khan last week hit the streets in her Tooting seat with placards saying 'Vote Rosena, vote Remain' according to photos posted on social media.
The NHS medic took over from Sadiq Khan in the south London seat in 2016 after he became London mayor.
Dr Khan, 42, posted the image on Twitter with the message: 'Out on the campaign trail with an amazing @tootinglabour team!
'Our new correx boards arrived today, my message is clear: Vote Rosena, Vote Remain!'