The aim of this study is to examine the practice of careers guidance in Hong Kong secondary schools by means of a comprehensive research into the roles of careers teachers. It inquires into the expectations and perceptions of careers teachers themselves and the key members of their role set - the principal, students and parents of the school. A proposed 'Model of Careers Teachers' Roles' derived from the academic literature in the context of Hong Kong is also examined through a number of key questions. This study explores the importance of future policy planning and development of careers guidance to facilitate the school to work transition of students. Careers teachers' roles are presented as multifaceted and reliant on sound knowledge, skills and theories from continued professional development. In this study, the methodological tools are a survey and three case studies. The breadth of evidence is provided by 82 valid replies to the questionnaire survey, and the depth of the grounds is derived from three case studies comprising interviews, documentary analysis and observation. Then, the roles of careers teachers in Hong Kong secondary schools are analysed, and the various aspects of their roles and duties are identified. Factors that help and hinder the provision of careers guidance are also examined. Finally, a 'Comprehensive Counselling and Guidance Programme' is proposed as a guideline for careers teachers to enhance their performance of duties and to improve their services for their students at all levels in their schools.