Stephanie Todd, who previously represented the Tories on Richmondshire Council, was joined by Scarborough Council independents Sam Cross and Mick Jay-Hanmer in making the move.
Ukip also confirmed its slate of candidates for the county council elections will involve three authors including GP Taylor who first revealed his support for the party last year.
The three current councillors plan to continue in their district council roles and will contest the North Yorkshire County Council elections as Ukip candidates.
Mrs Todd, a 52-year-old self-employed florist, did not tell her former Conservative colleagues about her decision ahead of her announcement yesterday.
She said: “I want to be part of a party which is supporting this country and its people and a party which actually listens to the people and takes notice of their concerns.”
GP Taylor is joined as a Ukip candidate by fellow authors Mark Harland and Heath Samples.
He said: “I am sick to the back teeth of what is happening to my fantastic country, seeing it being ground down.
“I was a Conservative supporter and have donated money to them but I now believe they are out of touch with people.”
Ukip is already hoping to build on the momentum of the Eastleigh by-election where the party forced the Conservatives into third place.
It was also recently buoyed by the high profile defection of Victoria Ayling, a Lincolnshire councillor who came close to the winning the Great Grimsby seat for the Conservatives at the last General Election and who was at Ukip’s launch event in Scarborough yesterday.
The vast majority of Yorkshire councils will not hold any elections this year.
However, every North Yorkshire County Council seat and the Doncaster mayoralty will be contested on Thursday May 2.