Lib Dem leader Paul Hodgkinson has called the 'moron' label "disgusting"
Councillors dubbed "morons" by rivals via social networking site Facebook say they may report the insult to the local government watchdog.
Cotswold District Council leader Lynden Stowe and fellow Tory Chris Roberts said Lib Dem rivals "have a reputation... for being morons".
Leader of the council's Lib Dem group Paul Hodgkinson said: "It's disgusting, not just for me but for my colleagues."
He added colleagues were considering an official Code of Conduct complaint.
In the online exchange on 14 October, Mrs Roberts and Mr Stowe wrote open messages which referred to Lib Dems as "morons".
The Lib Dem group is now considering whether to complain under the Code of Conduct, which is overseen by Standards for England, the government's local authority regulatory body.
Mr Hodgkinson added: "I'm a bit confused as to how someone could do this in public. The term is not nice."
The Conservative group has a majority on the council.
Mr Stowe and Mrs Roberts have issued a joint statement which reads: "These were private comments which were available only to our authorised 'friends' on Facebook.
"It's clear one of our 'friends' is not a friend but a Lib Dem sympathiser who has abused the system and infiltrated private pages not available in the wider public domain.
"To us, it reinforces just how low Liberal Democrats will stoop."