The ex-Glasgow Govan MP was shocked to be turned away from Wednesday's independence debate after being invited by the Edinburgh University Socialist Society [EUSS].
The group was incensed at claims made by Mr Sillars' on the BBC's Question Time last month about the controversial Liberal Democrat Lord Rennard.
When asked whether the peer should apologise after being cleared of claims he had sexually harrassed female party members, Mr Sillars had dismissed it as 'not the most serious issue facing the country.'
Mr Sillars, 76, said last night his integrity and reputation had been damaged by the EUSS's treatment of him. The EUSS said it contravened its safe spaces policy, which operates a zero tolerance approach to discrimination.
He is considering his next move to defend a 'defamation action against my character."
Mr Sillars said: "I was met at the door by two organisers and told me there was a problem with my comments on Question Time. I was taken aback.
"The implication is that women would not feel safe with me in the same room. What would I have done to make women feel unsafe is beyond me.
"I stand by everything. . I said [Lord Rennard] wasn't a priority in the face of issues such as four million Syrian refugees in the snow, Iraq and Afganistan and the expansion of food banks, poverty and payday loans.
The EUSS said: "Mr Sillars' invitation was indeed rescinded at the last mintue when his remarks on Question Time were brought to light.
"It was felt that Mr Sillars' remarks trivialised the allegations surrounding Lord Rennard.
"It was therefore felt that Mr Sillars' presence at one of our events would be inappropriate to our values as an organisation, as well as in direct contravention of our safe spaces policy, as well as the safe spaces policy of the university and the Edinburgh University Students' Association."