The Just Say Naw meeting was due to be staged on May 6, but Mr Galloway says officials at the MacRobert Centre in Stirling decided they could not accept the previously confirmed booking.
Mr Galloway, who said an attempt to book at Howden Park Centre in Livingston and the Citizens in Glasgow, had previously been blocked, said of the latest development: "This is blatant censorship."
He said the reason for taking legal action was that he had lost thousands of pounds through the pulping of 50,000 tour brochures that contained the "confirmed" Stirling event.
Robin Holden, events and project co-ordinator at the MacRobert told Mr Galloway in an email: "I passed it (details of the event) onto both our chief executive and creative director. Having reviewed the content and structure of the evening they have opted not go ahead with the booking at this time.
"I do apologise for any inconvenience this may cause but unfortunately the final decision rests with them. I hope the rest of the tour goes well for you."
The former Labour politician, now Respect MP for Bradford, who spoke to a packed house at the Assembly Rooms in Edinburgh on Monday, said: "I say to the censors of Stirling that I will be heard in your town, in spite of your efforts to stop me."
After the Edinburgh rally, Mr Galloway said he would like to be prime minister of an independent Scotland.
Nobody was available at the theatre for comment.