The council made the decision after studying a Select Committee report on personal, social and health education (PSHE) in schools. It concluded that a fundamental review of sex education in schools is needed to combat teenage pregnancy rates.
The advisory group will include members of Kent Youth County Council and will try to ensure all schools teach sex and relationships education in a relevant way. Schools are not obliged to teach sex education within PSHE.
Paul Carter, leader of Kent County Council, said: "This is a massively significant piece of work that needs to be carried out fast to get our schools to improve the education they are providing."