Objective: Drawing on the perceptions of various key stakeholders, the paper explores the strengths and limitations of involving civil society organisations in the delivery of HIV and AIDS and sexuality education in South African schools. Design: Qualitative study with a cross-sectional design. Setting: Research was conducted at 16 public secondary schools in KwaZulu-Natal, Gauteng and Mpumalanga provinces in South Africa. Methods: Focus group discussions were held with Grade 9 and 11 learners, aged 14-18 years, and interviews with Life Orientation educators, Heads of Department and local civil society organisations. Results: School engagement with civil society organisations may include (1) the delivery of life skills programmes and talks, (2) assisting learners with accessing support services, and (3) the provision of teaching resources for Life Orientation educators and schools. The involvement of external organisations was often favoured for the youthful age of facilitators, shared personal experiences, novel learning activities and the overall separateness from schooling structures whereby personal disclosure or the provision of services were unlikely to influence school functioning. On-site Life Orientation educators were favoured for their consistent availability and familiarity, discipline, teaching experience and classroom management skills. Conclusion: Opportunities exist for collaboration between Life Orientation educators and civil society organisations in the future delivery of sexuality education. Potential partnerships may allow mutual expertise to be harnessed and alleviation of time and resource pressures. However, collaboration requires dialogue to clarify roles and to minimise resistance in schools. Effective monitoring and evaluation at a national or provincial level is also needed to help schools assessing the suitability of particular civil society organisations.