In chilling social media posts seen by Express.co.uk, the hard-left activists warned of mass social unrest in the event of a Tory victory.
They raised the possibility of riots, protests and strikes – and even a revolution – if Theresa May remains Prime Minister.
The page boasts more than 55,000 fans but is not affiliated with the left-winger or his party.
Asked what would happen if Mr Corbyn loses the election, one user wrote: "National strike, riots, social unrest.
"Either the government resigns or there's civil war. That would be a catastrophe, that's exactly what the Tories want."
Another commented: "All out strikes and riots. I will become 2017 Robin Hood. I'll rob the elites and feed the poor and working families."
Jeremy Corbyn supporters made the shocking comments in a Facebook group Election 2017 LIVE Wed, May 31, 2017
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The social media page is not affiliated with Corbyn or the Labour Party
If we don't win the election, we need a revolution!
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Others raised the possibility of a socialist revolution to overthrow Mrs May's government.
One Labour activist said: "If we don't win the election, we need a revolution!"
And another warned: "Do it and hit [the] streets, mass revolution. Fill up the streets, take our homeland back, JC all the way."
Labour activists said a Tory victory would spark a 'mass revolution'
But other supporters of Mr Corbyn warned against violence.
One wrote wrote: "As Jeremy Corbyn calls for peace in the world, you would resort to violence?
"Jeremy would not resort to violence, neither should you. If you don't have any other excuse to be peaceful, use that."
Another added: "No violence. Calm, organised lawful protest. We all need to start understanding the law and then using it to our advantage."