The Tory MP said he was extremely grateful to the UK for deciding to leave the European Union before Mr Juncker's "nightmare" plans came into effect.
Speaking to Nick Ferrari on LBC, Mr Rees-Mogg said: "I’m just so glad we’re leaving and are getting out of the possibility of a United States of Europe, which has always been the plan of the Commission.
"If you look at the response of senior European leaders to Monsieur Juncker, I think he’s in cloud cuckoo land. I don’t think there’s any demand for this."
GETTY/LBCMr Rees-Mogg said Juncker's plans were a nightmare for EU member states
He said Juncker's proposals to expand EU powers were coming at a time of great in-fighting between the big wigs in Brussels and other member states unwilling to stand by EU orders.
Mr Rees-Mogg continued: "It’s happening at a point when the Commission is not only dealing with Brexit but also