Sexual and reproductive health (SRH) programmes for young people have a high priority in many low- and middle income countries (LMICs). However, little is known about economic aspects of these programmes. More information is needed to support policy making and to accelerate implementation of these programmes. This multi-country PhD thesis provides new evidence on costs and cost-effectiveness of young people’s SRH programmes in resource limited settings. The six research papers are intended for national healthcare policy makers and public health programme managers in LMICs, and personnel of international organizations supporting their work. The World Health Organization (WHO) recommends simultaneous implementation of health promotion and healthcare services. This thesis focuses on economic evaluations of these two pillars in the context of young people’s SRH. It is organized in two thematic sections; first school-based sexuality education (SBSE) programmes, and second youth-friendly sexual and reproductive health (YFSRH) services.