In this grounded theory study the aim was to explore professionals' experiences of promotion of adolescents' sexual health, and views on inter-professional collaboration in relation to this subject. Data collection was by five focus group interviews and two pair interviews with professionals working with sexual health promotion in health care and schools. The results showed that professionals were reaching out to young people through competence and trusting relationships along with working on a broader front. In conclusion, professionals need to be knowledgeable about the world of young people, accessible and able to offer adequate support, and improve their inter-professional collaborations.